Fix regression for creating repositories in root-based containers (#172)

Due to #160 it was no longer possible to create repositories in root-based containers. This was caused by the missing `/tmp/gitea` directory in that image. It was dynamically created by Gitea internal functionality with less privileges than necessary.

Explicitly creating the directory and set proper permissions fix this.

Fixes: #171

Co-authored-by: JustusBunsi <sk.bunsenbrenner@gmail.com>
Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/172
Reviewed-by: luhahn <luhahn@noreply.gitea.io>
Reviewed-by: 6543 <6543@obermui.de>
Co-authored-by: justusbunsi <justusbunsi@noreply.gitea.io>
Co-committed-by: justusbunsi <justusbunsi@noreply.gitea.io>

templates/gitea/statefulset.yaml

@@ -48,12 +48,16 @@ spec:
               value: /data/gitea
             - name: GITEA_WORK_DIR
               value: /data
+            - name: GITEA_TEMP
+              value: /tmp/gitea
             {{- if .Values.statefulset.env }}
             {{- toYaml .Values.statefulset.env | nindent 12 }}
             {{- end }}
           volumeMounts:
             - name: init
               mountPath: /usr/sbin
+            - name: temp
+              mountPath: /tmp
             - name: config
               mountPath: /etc/gitea/conf
             - name: data