Fix GitHub workflow defs + bring in line with other repos.

Just copied them over from another repo. (I picked frontend as the
pattern.)

The deploy workflow was failing with `failed to fetch workflow` because
it was referring to
`govuk-infrastructure/.github/workflows/build-and-push-image.yml@add-version-tag`
(which no longer exists).

.github/workflows/deploy.yml

@@ -1,6 +1,6 @@
 name: Deploy
 
-run-name: Deploy ${{ inputs.gitRef || github.ref_name  }} to ${{ inputs.environment || 'integration' }}
+run-name: Deploy ${{ inputs.gitRef || github.event.release.tag_name  }} to ${{ inputs.environment || 'integration' }}
 
 on:
   workflow_dispatch:
@@ -23,16 +23,16 @@ on:
 
 jobs:
   build-and-publish-image:
-    if: github.event_name == 'workflow_dispatch' || startsWith(github.ref_name, 'v') 
+    if: github.event_name == 'workflow_dispatch' || startsWith(github.event.release.tag_name, 'v')
     name: Build and publish image
-    uses: alphagov/govuk-infrastructure/.github/workflows/build-and-push-image.yml@add-version-tag
+    uses: alphagov/govuk-infrastructure/.github/workflows/build-and-push-image.yml@main
     with:
-      gitRef: ${{ inputs.gitRef || github.ref_name }}
+      gitRef: ${{ inputs.gitRef || github.event.release.tag_name }}
     secrets:
       AWS_ACCESS_KEY_ID: ${{ secrets.AWS_GOVUK_ECR_ACCESS_KEY_ID }}
       AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_GOVUK_ECR_SECRET_ACCESS_KEY }}
   trigger-deploy:
-    name: Trigger deploy to ${{ github.event.inputs.environment }}
+    name: Trigger deploy to ${{ inputs.environment || 'integration' }}
     needs: build-and-publish-image
     uses: alphagov/govuk-infrastructure/.github/workflows/deploy.yml@main
     with:

.github/workflows/release.yml

@@ -1,8 +1,5 @@
 name: Release
 
-permissions:
-  contents: write
-
 on:
   workflow_dispatch:
   workflow_run:
@@ -14,9 +11,6 @@ jobs:
   release:
     if: github.event_name == 'workflow_dispatch' || github.event.workflow_run.conclusion == 'success'
     name: Release
-    # TODO: switch this to track main branch
-    uses: alphagov/govuk-infrastructure/.github/workflows/release.yml@add-version-tag
+    uses: alphagov/govuk-infrastructure/.github/workflows/release.yml@main
     secrets:
       GH_TOKEN: ${{ secrets.GOVUK_CI_GITHUB_API_TOKEN }}
-
-