Update testing matrix to include WP 5.7.2

Author: fdalcin

.github/workflows/.pipeline.yml

@@ -13,9 +13,9 @@ jobs:
       matrix:
         php: [ 7.3 ]
         os: [ ubuntu-18.04 ]
-        wordpress: [ 5.6.2 ]
+        wordpress: [ 5.6.2, 5.7.2 ]
 
-    name: Test - PHP ${{ matrix.php }}
+    name: Test - PHP ${{ matrix.php }} - WP ${{ matrix.wordpress }}
 
     env:
       WP_VERSION: ${{ matrix.wordpress }}