Bump actions/cache from 2.1.6 to 4.1.2

Bumps [actions/cache](https://github.com/actions/cache) from 2.1.6 to 4.1.2.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v2.1.6...v4.1.2)

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/ci.yaml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/cache@v2.1.6
+      - uses: actions/cache@v4.1.2
         with:
           path: |
             ~/.cargo/registry
@@ -39,7 +39,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/cache@v2.1.6
+      - uses: actions/cache@v4.1.2
         with:
           path: |
             ~/.cargo/registry
@@ -68,7 +68,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/cache@v2.1.6
+      - uses: actions/cache@v4.1.2
         with:
           path: |
             ~/.cargo/registry
@@ -98,7 +98,7 @@ jobs:
   #   steps:
   #     - uses: actions/checkout@v2
   #     # Uses the cache done in the parent job (compile) with the same "key"
-  #     - uses: actions/cache@v2.1.6
+  #     - uses: actions/cache@v4.1.2
   #       with:
   #         path: |
   #           ~/.cargo/registry
@@ -114,7 +114,7 @@ jobs:
 #     steps:
 #       - uses: actions/checkout@v2
 #       # Uses the cache done in the parent job (compile) with the same "key"
-#       - uses: actions/cache@v2.1.6
+#       - uses: actions/cache@v4.1.2
 #         with:
 #           path: |
 #             ~/.cargo/registry
@@ -131,7 +131,7 @@ jobs:
   #     - uses: actions/checkout@v2
   #   # Sets up a cache to be used on other subsequent jobs.
   #   # subsequent jobs must use the "needs" field and reference this job.id "compile".
-  #     - uses: actions/cache@v2.1.6
+  #     - uses: actions/cache@v4.1.2
   #       with:
   #         path: |
   #           ~/.cargo/registry