change the docker images

Author: sgmv

.github/workflows/ci.yml

@@ -9,7 +9,6 @@ on:
 
 env:
   CARGO_TERM_COLOR: 'always'
-  TARPAULIN_VERSION: '0.35.1'
 
 jobs:
   test:
@@ -32,7 +31,7 @@ jobs:
   coverage:
     runs-on: ubuntu-latest
     container:
-      image: xd009642/tarpaulin:${{ env.TARPAULIN_VERSION }}
+      image: xd009642/tarpaulin:0.35.1
       options: --security-opt seccomp=unconfined
     needs: test
     steps: