Merge pull request #13 from iotaledger/update_gh_actions

fix: update cache and checkout actions to v4

Author: lzpap

.github/workflows/gh-mdbook.yml

@@ -10,7 +10,7 @@ jobs:
         runs-on: ubuntu-latest
         steps:
             - name: Checkout
-              uses: actions/checkout@v2
+              uses: actions/checkout@v4
 
             # Install Rust package manager
             #
@@ -28,7 +28,7 @@ jobs:
                 path: ~/.cargo/registry
                 key: ${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
             - name: Cache cargo index
-              uses: actions/cache@v1
+              uses: actions/cache@v4
               with:
                   path: ~/.cargo/git
                   key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}

.github/workflows/markdownlint.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Markdown Linting
         uses: avto-dev/markdown-lint@v1.5.0
         with: