ci: use StepSecurity's maintained actions (#6343)

Each third-party action that StepSecurity publishes a secure drop-in
replacement for now uses that replacement, pinned to a commit with its
version as a comment. Versions follow what we used: the newest
StepSecurity release in the same major, or the closest major they
publish. dtolnay/rust-toolchain refs that named a toolchain (stable,
nightly, 1.76) become the replacement's `toolchain` input.

.github/workflows/printing.yml

@@ -81,12 +81,13 @@ jobs:
             pkg-config libxkbcommon-dev libwayland-dev libx11-dev libxcursor-dev libxrandr-dev \
             libxi-dev libgtk-3-dev libfontconfig1-dev libfreetype-dev libvulkan1 mesa-vulkan-drivers
 
-      - uses: dtolnay/rust-toolchain@b725eda525362e7cf34af9a7243cac1e3f01a7ec # stable
+      - uses: step-security/dtolnay-rust-toolchain@8dd607977d06adf4ed49b190381e74c17a9dd25f # v1.0.0
         with:
+          toolchain: stable
           components: rustfmt, clippy
           targets: wasm32-unknown-unknown
 
-      - uses: Swatinem/rust-cache@d1527c8f67ef9af357290475d4af4b0fab8f12e0 # v2.9.3
+      - uses: step-security/rust-cache@8871c8ba063416da7c32246932ea6ae08700453e # v2.9.2
         with:
           save-if: ${{ github.ref == 'refs/heads/main' }}