Temporary revert GPG feature for semver based retagging (#373)

Feature #343 happens to be a breaking change when enabling `.Values.signing` but not specifying
any of the new private key properties. Tag `v6.0.2` is therefore not following semantic versioning.

This temporarily reverts commit b8f0310c43 and a fix-up commit 57a1cd27d9
to retag 6.0.2 as 6.0.3.

Co-authored-by: justusbunsi <sk.bunsenbrenner@gmail.com>
Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/373
Reviewed-by: techknowlogick <techknowlogick@gitea.io>
Reviewed-by: luhahn <luhahn@noreply.gitea.io>

.drone.yml

@@ -23,15 +23,6 @@ steps:
   - helm dependency update
   - helm template --debug gitea-helm .
 
-- name: helm unittests
-  pull: always
-  image: alpine:3.16
-  commands:
-  - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing make helm git bash
-  - helm plugin install https://github.com/heyhabito/helm-unittest
-  - helm dependency update
-  - make unittests
-
 - name: verify readme
   pull: always
   image: alpine:3.16