Bump actions/cache from 2.1.6 to 2.1.7

Bumps [actions/cache](https://github.com/actions/cache) from 2.1.6 to 2.1.7.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](https://github.com/actions/cache/compare/v2.1.6...v2.1.7)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
 
     - name: Cache ARM toolchains
       id: cache-toolchains
-      uses: actions/cache@v2.1.6
+      uses: actions/cache@v2.1.7
       with:
         path: |
           ~/gcc-arm-${{ env.toolchain-version }}-x86_64-arm-none-eabi
@@ -74,7 +74,7 @@ jobs:
 
     - name: Cache boot files
       id: cache-boot-files
-      uses: actions/cache@v2.1.6
+      uses: actions/cache@v2.1.7
       with:
         path: |
           sdcard/armstub8-rpi4.bin
@@ -92,14 +92,14 @@ jobs:
 
     - name: Cache WLAN firmware
       id: cache-wlan-firmware
-      uses: actions/cache@v2.1.4
+      uses: actions/cache@v2.1.7
       with:
         path: sdcard/firmware
         key: cache-wlan-firmware-${{ hashFiles(join(env.wlan-home, '/firmware/Makefile')) }}
 
     - name: Cache ARM toolchains
       if: steps.cache-boot-files.outputs.cache-hit != 'true'
-      uses: actions/cache@v2.1.6
+      uses: actions/cache@v2.1.7
       with:
         path: |
           ~/gcc-arm-${{ env.toolchain-version }}-x86_64-arm-none-eabi
@@ -148,7 +148,7 @@ jobs:
 
     - name: Cache GeneralUser GS SoundFont
       id: cache-generaluser-gs
-      uses: actions/cache@v2.1.6
+      uses: actions/cache@v2.1.7
       with:
         path: GeneralUser GS v1.511
         key: cache-generaluser-gs-1.511