Update md link checker (#7709)

* CI: ignore %20 for md link checker

* CI: update to a new action release that fixes %20 issue

substrate/.github/allowed-actions.js

@@ -3,5 +3,5 @@
 // not listed here, CI will fail.
 
 module.exports = [
-    'gaurav-nelson/github-action-markdown-link-check@e3c371c731b2f494f856dc5de7f61cea4d519907', // gaurav-nelson/github-action-markdown-link-check@v1.0.8
+    'gaurav-nelson/github-action-markdown-link-check@7481451f70251762f149d69596e3e276ebf2b236', // gaurav-nelson/github-action-markdown-link-check@v1.0.8
 ]

substrate/.github/workflows/md-link-check.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - uses: gaurav-nelson/github-action-markdown-link-check@e3c371c731b2f494f856dc5de7f61cea4d519907
+    - uses: gaurav-nelson/github-action-markdown-link-check@7481451f70251762f149d69596e3e276ebf2b236
       with:
         use-quiet-mode: 'yes'
         config-file: '.github/workflows/mlc_config.json'

substrate/.github/workflows/mlc_config.json

@@ -1,13 +1,7 @@
 {
     "ignorePatterns": [
         {
-            "pattern": "^https://crates.io"
-        }
-    ],
-    "replacementPatterns": [
-        {
-          "pattern": "%20",
-          "replacement": " "
+            "pattern": "^https://crates.io",
         }
     ]
 }