Update GitHub Actions CI

The following updates are performed:
* update actions/cache to v4
* update actions/checkout to v4

.github/workflows/ci.yml

@@ -119,13 +119,13 @@ jobs:
             git config --global pack.threads 0
             ! command -v cmake &> /dev/null || echo "B2_FLAGS=--nowide-enable-cmake" >> $GITHUB_ENV
 
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           # For coverage builds fetch the whole history, else only 1 commit using a 'fake ternary'
           fetch-depth: ${{ matrix.coverage && '0' || '1' }}
 
       - name: Cache ccache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         if: env.B2_USE_CCACHE
         with:
           path: ~/.ccache
@@ -135,7 +135,7 @@ jobs:
             ${{matrix.os}}-${{matrix.container}}-${{matrix.compiler}}
 
       - name: Fetch Boost.CI
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: boostorg/boost-ci
           ref: master
@@ -260,7 +260,7 @@ jobs:
     runs-on: windows-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Setup MSYS2 environment
         uses: msys2/setup-msys2@v2
@@ -271,7 +271,7 @@ jobs:
           pacboy: gcc:p cmake:p ninja:p
 
       - name: Fetch Boost.CI
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: boostorg/boost-ci
           ref: master
@@ -320,9 +320,9 @@ jobs:
     runs-on: ${{matrix.os}}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Fetch Boost.CI
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: boostorg/boost-ci
           ref: master

.github/workflows/ci_tests.yml

@@ -48,10 +48,10 @@ jobs:
       DEP_DIR: ${{github.workspace}}/dependencies
       BOOST_VERSION: 1.56.0
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Sanity check version
       run: grep -E 'set\(_version [0-9]' CMakeLists.txt
-    - uses: actions/cache@v1
+    - uses: actions/cache@v4
       id: cache-boost
       with:
         path: ${{env.DEP_DIR}}
@@ -64,7 +64,7 @@ jobs:
       if: matrix.standalone == 'Boost'
       run: echo "BOOST_ROOT=${DEP_DIR//\\/\/}/boost_${BOOST_VERSION//./_}" >> $GITHUB_ENV
     # Install Boost
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       if: matrix.standalone == 'Boost' && steps.cache-boost.outputs.cache-hit != 'true'
       with:
         repository: boostorg/boost
@@ -125,7 +125,7 @@ jobs:
   CreateDocuTest:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
       - name: Create documentation
         run: |
             sudo apt-get install -y doxygen
@@ -134,9 +134,9 @@ jobs:
   CreateBoostDocuTest:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Fetch Boost.CI
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: boostorg/boost-ci
           ref: master
@@ -153,7 +153,7 @@ jobs:
   CheckFormatting:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: DoozyX/[email protected]
         with:
           exclude: './doc'

.github/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
       DEP_DIR: ${{github.workspace}}/dependencies
       BOOST_VERSION: 1.56.0
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Extract tag name
         id: get_tag
         run: |