Bump outdated GitHub Actions to current major versions

actions/checkout v2/v3 -> v4 and actions/setup-python v2/v4 -> v5
across clang-tidy.yml, docs.yml, and unittests.yml. Addresses the
Node 20 deprecation warning surfaced by the new clang-tidy workflow
run.

Author: ThoSe1990

.github/workflows/clang-tidy.yml

@@ -15,7 +15,7 @@ jobs:
       HOME: /root
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 

.github/workflows/docs.yml

@@ -14,7 +14,7 @@ jobs:
     container: ghcr.io/those1990/sphinx-docs:1.0
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Build docs
       # TODO: new image w/ cmake
@@ -29,7 +29,7 @@ jobs:
           mv ./_build/html/ ../pages/
 
       - name: Setup Pages
-        uses: actions/configure-pages@v3
+        uses: actions/configure-pages@v5
 
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v3

.github/workflows/unittests.yml

@@ -26,7 +26,7 @@ jobs:
             conan_profile: -pr clang
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Build
         run: |
@@ -52,10 +52,10 @@ jobs:
     runs-on: windows-latest 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Set up Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v5
         with:
           python-version: '3.12'
 
@@ -94,10 +94,10 @@ jobs:
       packages: read
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Set up Python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           python-version: '3.12'