Bump Swatinem/rust-cache from 1 to 2

Bumps [Swatinem/rust-cache](https://github.com/swatinem/rust-cache) from 1 to 2.
- [Release notes](https://github.com/swatinem/rust-cache/releases)
- [Changelog](https://github.com/Swatinem/rust-cache/blob/master/CHANGELOG.md)
- [Commits](Swatinem/rust-cache@v1...v2)

---
updated-dependencies:
- dependency-name: Swatinem/rust-cache
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/benchmarks.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - run: rustup toolchain update nightly && rustup default nightly
-      - uses: Swatinem/rust-cache@v1
+      - uses: Swatinem/rust-cache@v2
       - name: run benchmark
         run: cargo +nightly bench | tee benchmark_output.txt
       - name: store benchmark result

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
           toolchain: stable
           override: true
           components: rustfmt, clippy
-      - uses: Swatinem/rust-cache@v1
+      - uses: Swatinem/rust-cache@v2
       - uses: actions-rs/cargo@v1
         name: formatting check
         with:
@@ -50,7 +50,7 @@ jobs:
           profile: minimal
           toolchain: ${{ matrix.toolchain }}
           override: true
-      - uses: Swatinem/rust-cache@v1
+      - uses: Swatinem/rust-cache@v2
       - uses: actions-rs/cargo@v1
         name: thumbv6m-none-eabi check
         if: ${{ matrix.use_std == 'y' }}
@@ -87,7 +87,7 @@ jobs:
           profile: minimal
           toolchain: ${{ matrix.toolchain }}
           override: true
-      - uses: Swatinem/rust-cache@v1
+      - uses: Swatinem/rust-cache@v2
       - uses: actions-rs/cargo@v1
         name: thumbv6m-none-eabi build
         if: ${{ matrix.use_std == 'y' }}
@@ -119,7 +119,7 @@ jobs:
           profile: minimal
           toolchain: ${{ matrix.toolchain }}
           override: true
-      - uses: Swatinem/rust-cache@v1
+      - uses: Swatinem/rust-cache@v2
       - uses: actions-rs/cargo@v1
         name: std test all
         with:
@@ -139,7 +139,7 @@ jobs:
           profile: minimal
           toolchain: ${{ matrix.toolchain }}
           override: true
-      - uses: Swatinem/rust-cache@v1
+      - uses: Swatinem/rust-cache@v2
       - uses: actions-rs/cargo@v1
         name: std doc check
         env:

.github/workflows/rustdoc.yml

@@ -18,7 +18,7 @@ jobs:
           toolchain: stable
           override: true
 
-      - uses: Swatinem/rust-cache@v1
+      - uses: Swatinem/rust-cache@v2
 
       - uses: actions-rs/cargo@v1
         name: build docs