CI: Trigger full release after git tag --push

This fixes the regex used to detect tagged releases and runs the
`build-push-image` job for tagged releases.

Fixes #1351.

.github/workflows/ci.yml

@@ -1,7 +1,7 @@
 name: Cryptol
 on:
   push:
-    tags: ["?[0-9]+.[0-9]+(.[0-9]+)?"]
+    tags: ["[0-9]+.[0-9]+(.[0-9]+)?"]
     branches: [master, "release-**"]
   pull_request:
   schedule:
@@ -311,7 +311,7 @@ jobs:
   build-push-image:
     runs-on: ubuntu-20.04
     needs: [config]
-    if: github.event_name == 'schedule' || github.event_name == 'workflow_dispatch'
+    if: github.event_name == 'schedule' || github.event_name == 'workflow_dispatch' || needs.config.outputs.release == 'true'
     strategy:
       fail-fast: false
       matrix: