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>

Chart.lock

@@ -1,9 +1,9 @@
 dependencies:
-- name: memcached
-  repository: oci://registry-1.docker.io/bitnamicharts
-  version: 6.3.13
-- name: postgresql
-  repository: oci://registry-1.docker.io/bitnamicharts
-  version: 12.2.6
+  - name: memcached
+    repository: oci://registry-1.docker.io/bitnamicharts
+    version: 6.3.13
+  - name: postgresql
+    repository: oci://registry-1.docker.io/bitnamicharts
+    version: 12.2.6
 digest: sha256:7a37054b0ae841314b1e309fec6f1edc0f22f77161ee915ebfb1ce011457884c
 generated: "2023-03-28T21:20:51.230043+02:00"