feat: s/alpha/master/

Author: erikmd

.github/workflows/build-coq-demo.yml

@@ -37,7 +37,7 @@ jobs:
     # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
     - uses: actions/checkout@v2
 
-    - uses: erikmd/docker-coq-action@alpha
+    - uses: erikmd/docker-coq-action@master
       id: docker-coq-action
       with:
         opam_file: 'coq-demo.opam'
@@ -71,7 +71,7 @@ jobs:
       max-parallel: 4
     steps:
     - uses: actions/checkout@v2
-    - uses: erikmd/docker-coq-action@alpha
+    - uses: erikmd/docker-coq-action@master
       id: docker-mathcomp-action
       with:
         opam_file: './coq-demo.opam'