Fixed GiHub action warning

Upgraded actions/checkout@v2 to @V3 in pr-validation.yml and release.yml because of the following warning.

Node.js 12 actions are deprecated. For more information see: https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/. Please update the following actions to use Node.js 16: actions/checkout@v2

Author: ckadluba

.github/workflows/pr-validation.yml

@@ -11,7 +11,7 @@ jobs:
   build-and-test:
     runs-on: windows-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Run build and tests
         run: ./Build.ps1

.github/workflows/release.yml

@@ -11,7 +11,7 @@ jobs:
   build-and-release:
     runs-on: windows-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Run build
         run: ./Build.ps1 -SkipTests