diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 3a211da..0916b1a 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        php_version: [7.2, 7.3, 7.4, 8.0, 8.1, 8.2]
+        php_version: ['7.2', '7.3', '7.4', '8.0', '8.1', '8.2']
     steps:
       - name: Check out repository
         uses: actions/checkout@v2
@@ -40,7 +40,7 @@ jobs:
       - name: tag latest image
         if: |
           success()
-          && ${{ matrix.php_version }} == 7.4
+          && ${{ matrix.php_version }} == '7.4'
         uses: actions-hub/docker@master
         with:
           args: tag dannecron/php-for-dev:7.4 dannecron/php-for-dev:latest
@@ -48,7 +48,7 @@ jobs:
       - name: push latest image to docker hub
         if: |
           success()
-          && ${{ matrix.php_version }} == 7.4
+          && ${{ matrix.php_version }} == '7.4'
         uses: actions-hub/docker@master
         with:
           args: push dannecron/php-for-dev:latest