Bump actions/checkout from 3 to 4

.github/workflows/check-arduino.yml

@@ -16,7 +16,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Arduino Lint
         uses: arduino/arduino-lint-action@v1

.github/workflows/check-keywords-txt.yml

@@ -22,7 +22,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install arduino-ci-script
         uses: per1234/install-arduino-ci-script-action@main

.github/workflows/compile-examples.yml

@@ -89,7 +89,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install ESP32 platform dependencies
         if: startsWith(matrix.board.fqbn, 'esp32:esp32')

.github/workflows/general-formatting-checks.yml

@@ -10,7 +10,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Check for files starting with a blank line
         run: find . -path './.git' -prune -or -type f -print0 | xargs -0 -L1 bash -c 'head -1 "$0" | grep --binary-files=without-match --regexp="^$"; if [[ "$?" == "0" ]]; then echo "Blank line found at start of $0."; false; fi'
@@ -20,7 +20,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Check for unnecessary use of true tabs
         run: find . -path './.git' -prune -or \( -not -name 'keywords.txt' -and -type f \) -exec grep --with-filename --line-number --binary-files=without-match --regexp=$'\t' '{}' \; -exec echo 'Tab found.' \; -exec false '{}' +
@@ -30,7 +30,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Check for trailing whitespace
         run: find . -path './.git' -prune -or -type f -exec grep --with-filename --line-number --binary-files=without-match --regexp='[[:blank:]]$' '{}' \; -exec echo 'Trailing whitespace found.' \; -exec false '{}' +
@@ -40,7 +40,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Check for non-Unix line endings
         run: find . -path './.git' -prune -or -type f -exec grep --files-with-matches --binary-files=without-match --regexp=$'\r$' '{}' \; -exec echo 'Non-Unix EOL detected.' \; -exec false '{}' +
@@ -50,7 +50,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Check for blank lines at end of files
         run: find . -path './.git' -prune -or -type f -print0 | xargs -0 -L1 bash -c 'tail -1 "$0" | grep --binary-files=without-match --regexp="^$"; if [[ "$?" == "0" ]]; then echo "Blank line found at end of $0."; false; fi'
@@ -60,7 +60,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Check for files that don't end in a newline
         # https://stackoverflow.com/a/25686825

.github/workflows/spell-check.yml

@@ -10,7 +10,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # See: https://github.com/codespell-project/actions-codespell/blob/master/README.md
       - name: Spell check

.github/workflows/sync-labels.yml

@@ -27,7 +27,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Download JSON schema for labels configuration file
         id: download-schema
@@ -99,7 +99,7 @@ jobs:
           echo "::set-output name=flag::--dry-run"
 
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Download configuration files artifact
         uses: actions/download-artifact@v3