Use clearer tag name for CI docker image (rescript-lang#6607)

Author: cknitt

.github/workflows/ci.yml

@@ -34,7 +34,7 @@ jobs:
  runs-on: ${{matrix.os}}
 
  container:
- image: ghcr.io/rescript-lang/rescript-ci-build:v1.2.0
+ image: ghcr.io/rescript-lang/rescript-ci-build:alpine-3.19-ocaml-4.14.1-02
 
  steps:
  # See https://github.com/actions/runner/issues/801#issuecomment-1374967227.