ci: use dtolnay/rust-toolchain in main build

.github/workflows/main-rust.yml

@@ -1,4 +1,4 @@
-name: Rust
+name: Rust Build & Publish
 
 on:
   push:
@@ -13,13 +13,19 @@ env:
 
 jobs:
   build:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - name: Checkout sources
+        uses: actions/checkout@v3
 
       - name: Cache Packages
-        uses: Swatinem/rust-cache@v1.0.1
+        uses: Swatinem/rust-cache@2
+
+      - name: Install stable toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          toolchain: stable
 
       - name: Build
         run: cargo build --release
@@ -28,7 +34,7 @@ jobs:
         continue-on-error: true
         run: cargo publish --no-verify --token ${{ secrets.CARGO_REGISTRY_TOKEN }}
       
-      - uses: actions/upload-artifact@v2.2.1
+      - uses: actions/upload-artifact@v3
         name: Upload a Build Artifact
         with:
           name: libreddit