ci: add caching to more jobs (#563)

More usage of the caching action to CI/deploy. Seems to save ~3-4 minutes on CI, not sure about deploy.

.github/workflows/ci.yml

@@ -42,6 +42,9 @@ jobs:
           toolchain: stable
           override: true
           components: rustfmt
+
+      - uses: Swatinem/rust-cache@v1
+      
       - run: cargo fmt --all -- --check
 
   # Check clippy.  Note that this doesn't check ARM.
@@ -64,6 +67,8 @@ jobs:
           override: true
           components: clippy
 
+      - uses: Swatinem/rust-cache@v1
+
       # TODO: Can probably put cache here in the future; I'm worried if this will cause issues with clippy though since cargo check breaks it; maybe wait until 1.52, when fix lands.
 
       - run: cargo clippy --all-targets --workspace -- -D warnings

.github/workflows/deployment.yml

@@ -187,6 +187,8 @@ jobs:
           override: true
           target: ${{ matrix.triple.target }}
 
+      - uses: Swatinem/rust-cache@v1
+
       - name: Build
         uses: actions-rs/cargo@v1
         with:

.github/workflows/nightly.yml

@@ -187,6 +187,8 @@ jobs:
           override: true
           target: ${{ matrix.triple.target }}
 
+      - uses: Swatinem/rust-cache@v1
+
       - name: Build
         uses: actions-rs/cargo@v1
         with: