Bump alpine version in CI (#384)

To fix package installation issues. Apparently installing `helm` in 3.16 fails constantly.

Co-authored-by: pat-s <patrick.schratz@gmail.com>
Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/384
Reviewed-by: justusbunsi <justusbunsi@noreply.gitea.io>
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: pat-s <pat-s@noreply.gitea.io>
Co-committed-by: pat-s <pat-s@noreply.gitea.io>

.drone.yml

@@ -10,14 +10,14 @@ platform:
 steps:
 - name: helm lint
   pull: always
-  image: alpine:3.16
+  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:3.16
+  image: alpine:3.17
   commands:
   - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing helm
   - helm dependency update
@@ -25,7 +25,7 @@ steps:
 
 - name: verify readme
   pull: always
-  image: alpine:3.16
+  image: alpine:3.17
   commands:
   - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing make npm git
   - make readme
@@ -61,7 +61,7 @@ trigger:
 steps:
 - name: generate-chart
   pull: always
-  image: alpine:3.16
+  image: alpine:3.17
   commands:
     - apk add --no-cache -X http://dl-cdn.alpinelinux.org/alpine/edge/testing helm
     - apk add --no-cache curl