Update action versions (#28)

Author: DannyBedard

.github/workflows/rust.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Install Rust
         uses: actions-rs/toolchain@v1
         with:
@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Install Rust
         uses: actions-rs/toolchain@v1
         with:
@@ -42,7 +42,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Install Rust
         uses: actions-rs/toolchain@v1
         with: