feat(ci): pin CI to v0

Author: lucabello

.github/workflows/promote.yaml

@@ -14,7 +14,7 @@ on:
 jobs:
   promote:
     name: Promote
-    uses: canonical/observability/.github/workflows/charm-promote.yaml@main
+    uses: canonical/observability/.github/workflows/charm-promote.yaml@v0
     with:
       promotion: ${{ github.event.inputs.promotion }}
     secrets: inherit

.github/workflows/pull-request.yaml

@@ -8,5 +8,5 @@ on:
 jobs:
   pull-request:
     name: PR
-    uses: canonical/observability/.github/workflows/charm-pull-request.yaml@main
+    uses: canonical/observability/.github/workflows/charm-pull-request.yaml@v0
     secrets: inherit

.github/workflows/release.yaml

@@ -7,5 +7,5 @@ on:
 
 jobs:
   release:
-    uses: canonical/observability/.github/workflows/charm-release.yaml@main
+    uses: canonical/observability/.github/workflows/charm-release.yaml@v0
     secrets: inherit