MDL-80816 core: Bump actions to newer versions

All the new ones are Nodejs 20 based, because
Nodejs 16 is being deprecated @ GH environments.

https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20

.github/workflows/push.yml

@@ -23,10 +23,10 @@ jobs:
 
     steps:
       - name: Checking out code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Configuring node & npm
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
 
@@ -103,7 +103,7 @@ jobs:
           coverage: none
 
       - name: Checking out code from ${{ env.GITHUB_REF_SLUG }}
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setting up PHPUnit
         env:

.github/workflows/windows.yml

@@ -16,10 +16,10 @@ jobs:
           git config --global core.eol lf
 
       - name: Checking out code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Configuring node & npm
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
 
@@ -112,7 +112,7 @@ jobs:
           git config --global core.eol lf
 
       - name: Checking out code from ${{ env.GITHUB_REF_SLUG }}
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # Needs to be done after php is available, git configured and Moodle checkout has happened.
       - name: Setting up moodle-exttests service