Format all files with prettier VSCode plugin and add yamllint in CI (#413)

@justusbunsi to end my formatting mess... ;)

I am not fully sure myself about the linebreaks in `values.yaml` but I don't think there's an easy way to change that behavior.

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/413
Reviewed-by: justusbunsi <justusbunsi@noreply.gitea.io>
Co-authored-by: pat-s <patrick.schratz@gmail.com>
Co-committed-by: pat-s <patrick.schratz@gmail.com>

.drone.yml

@@ -8,51 +8,56 @@ platform:
   arch: arm64
 
 steps:
-- name: helm lint
-  pull: always
-  image: alpine:3.17
-  commands:
-  - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing helm
-  - helm lint
+  - name: helm lint
+    pull: always
+    image: alpine:3.17
+    commands:
+      - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing helm
+      - helm lint
 
-- name: helm template
-  pull: always
-  image: alpine:3.17
-  commands:
-  - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing helm
-  - helm dependency update
-  - helm template --debug gitea-helm .
+  - name: helm template
+    pull: always
+    image: alpine:3.17
+    commands:
+      - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing helm
+      - helm dependency update
+      - helm template --debug gitea-helm .
 
-- name: helm unittests
-  pull: always
-  image: alpine:3.17
-  commands:
-  - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing make helm git bash
-  - helm plugin install https://github.com/helm-unittest/helm-unittest
-  - helm dependency update
-  - make unittests
+  - name: helm unittests
+    pull: always
+    image: alpine:3.17
+    commands:
+      - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing make helm git bash
+      - helm plugin install https://github.com/helm-unittest/helm-unittest
+      - helm dependency update
+      - make unittests
 
-- name: verify readme
-  pull: always
-  image: alpine:3.17
-  commands:
-  - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing make npm git
-  - make readme
-  - git diff --exit-code --name-only README.md
+  - name: verify readme
+    pull: always
+    image: alpine:3.17
+    commands:
+      - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing make npm git
+      - make readme
+      - git diff --exit-code --name-only README.md
 
-- name: discord
-  pull: always
-  image: appleboy/drone-discord:1.2.4
-  environment:
-    DISCORD_WEBHOOK_ID:
-      from_secret: discord_webhook_id
-    DISCORD_WEBHOOK_TOKEN:
-      from_secret: discord_webhook_token
-  when:
-    status:
-    - changed
-    - failure
+  - name: yaml lint
+    pull: always
+    image: cytopia/yamllint:alpine-1
+    commands:
+      - yamllint -f colored .
 
+  - name: discord
+    pull: always
+    image: appleboy/drone-discord:1.2.4
+    environment:
+      DISCORD_WEBHOOK_ID:
+        from_secret: discord_webhook_id
+      DISCORD_WEBHOOK_TOKEN:
+        from_secret: discord_webhook_token
+    when:
+      status:
+        - changed
+        - failure
 
 ---
 kind: pipeline
@@ -65,40 +70,40 @@ platform:
 
 trigger:
   event:
-  - tag
+    - tag
 
 steps:
-- name: generate-chart
-  pull: always
-  image: alpine:3.17
-  commands:
-    - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing helm
-    - apk add --no-cache curl
-    - helm dependency update
-    - helm package --version "${DRONE_TAG##v}" ./
-    - mkdir gitea
-    - mv gitea*.tgz gitea/
-    - curl -L -o gitea/index.yaml https://dl.gitea.io/charts/index.yaml
-    - helm repo index gitea/ --url https://dl.gitea.io/charts --merge gitea/index.yaml
+  - name: generate-chart
+    pull: always
+    image: alpine:3.17
+    commands:
+      - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing helm
+      - apk add --no-cache curl
+      - helm dependency update
+      - helm package --version "${DRONE_TAG##v}" ./
+      - mkdir gitea
+      - mv gitea*.tgz gitea/
+      - curl -L -o gitea/index.yaml https://dl.gitea.io/charts/index.yaml
+      - helm repo index gitea/ --url https://dl.gitea.io/charts --merge gitea/index.yaml
 
-- name: upload-chart
-  pull: always
-  image: plugins/s3:latest
-  settings:
-    acl:
-      from_secret: aws_s3_acl
-    region:
-      from_secret: aws_s3_region
-    bucket:
-      from_secret: aws_s3_bucket
-    endpoint:
-      from_secret: aws_s3_endpoint
-    path_style:
-      from_secret: aws_s3_path_style
-    access_key:
-      from_secret: aws_access_key_id
-    secret_key:
-      from_secret: aws_secret_access_key
-    source: gitea/*
-    target: /charts
-    strip_prefix: gitea/
+  - name: upload-chart
+    pull: always
+    image: plugins/s3:latest
+    settings:
+      acl:
+        from_secret: aws_s3_acl
+      region:
+        from_secret: aws_s3_region
+      bucket:
+        from_secret: aws_s3_bucket
+      endpoint:
+        from_secret: aws_s3_endpoint
+      path_style:
+        from_secret: aws_s3_path_style
+      access_key:
+        from_secret: aws_access_key_id
+      secret_key:
+        from_secret: aws_secret_access_key
+      source: gitea/*
+      target: /charts
+      strip_prefix: gitea/