Update action version number in README.md (#23)

When using just @v2 the action results in an error: Unable to resolve action `nizarmah/auto-minify@v2`, unable to find version `v2`

README.md

@@ -26,7 +26,7 @@ steps:
   - uses: actions/checkout@v2
 
   - name: Auto Minify
-    uses: nizarmah/auto-minify@v2
+    uses: nizarmah/auto-minify@v2.1
 
   # Auto commits minified files to the repository
   # Ignore it if you don't want to commit the files to the repository 
@@ -45,7 +45,7 @@ steps:
   - uses: actions/checkout@v2
 
   - name: Auto Minify
-    uses: nizarmah/auto-minify@v2
+    uses: nizarmah/auto-minify@v2.1
     with:
       overwrite: true
 
@@ -66,7 +66,7 @@ steps:
   - uses: actions/checkout@v2
 
   - name: Auto Minify
-    uses: nizarmah/auto-minify@v2
+    uses: nizarmah/auto-minify@v2.1
     with:
       maxdepth: 1
 
@@ -87,7 +87,7 @@ steps:
   - uses: actions/checkout@v2
 
   - name: Auto Minify
-    uses: nizarmah/auto-minify@v2
+    uses: nizarmah/auto-minify@v2.1
     with:
       directory: 'js'
 
@@ -111,7 +111,7 @@ steps:
   - uses: actions/checkout@v2
 
   - name: Auto Minify
-    uses: nizarmah/auto-minify@v2
+    uses: nizarmah/auto-minify@v2.1
     with:
       directory: 'js'
       output: 'mini_js'