fix: align SENTRY_RELEASE env var with the release created by the Sentry action (#169)

The Sentry action receives the v-stripped version (e.g. 0.1.1) but the
app's SENTRY_RELEASE was set to IMAGE_TAG (e.g. v0.1.1). This caused
Sentry to auto-create a second release from incoming events, labelling it
(non-semver) instead of associating events with the properly created release.

Pass SENTRY_RELEASE as a separate query param through the Portainer webhook
(using the already-computed sentry_version output) and reference that in
compose.prod.yaml instead of IMAGE_TAG.

.github/workflows/ci.yml

@@ -244,4 +244,4 @@ jobs:
         env:
           PORTAINER_WEBHOOK: ${{secrets.PORTAINER_WEBHOOK}}
         run: |
-          curl -v -X POST "${PORTAINER_WEBHOOK}?IMAGE_TAG=${{steps.meta.outputs.tag}}" --fail-with-body
+          curl -v -X POST "${PORTAINER_WEBHOOK}?IMAGE_TAG=${{steps.meta.outputs.tag}}&SENTRY_RELEASE=${{steps.meta.outputs.sentry_version}}" --fail-with-body

compose.prod.yaml

@@ -10,7 +10,7 @@ services:
       MAILER_DSN: ${MAILER_DSN}
       MAILER_SENDER: ${MAILER_SENDER}
       SENTRY_DSN: ${SENTRY_DSN}
-      SENTRY_RELEASE: ${IMAGE_TAG}
+      SENTRY_RELEASE: ${SENTRY_RELEASE}
       SENTRY_ENVIRONMENT: ${SENTRY_ENVIRONMENT}
     labels:
       - "traefik.enable=true"