build(deps): bump actions/cache from v2.1.4 to v2.1.5 (libp2p#2050)

Bumps [actions/cache](https://github.com/actions/cache) from v2.1.4 to v2.1.5.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v2.1.4...1a9e213)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/ci.yml

@@ -20,13 +20,13 @@ jobs:
     - uses: actions/checkout@v2
 
     - name: Cache CARGO_HOME
-      uses: actions/cache@v2.1.4
+      uses: actions/cache@v2.1.5
       with:
         path: ~/.cargo
         key: cargo-home-${{ hashFiles('Cargo.toml') }}
 
     - name: Cache cargo build
-      uses: actions/cache@v2.1.4
+      uses: actions/cache@v2.1.5
       with:
         path: target
         key: cargo-build-target-${{ hashFiles('Cargo.toml') }}
@@ -81,13 +81,13 @@ jobs:
       run: apt-get install -y cmake
 
     - name: Cache CARGO_HOME
-      uses: actions/cache@v2.1.4
+      uses: actions/cache@v2.1.5
       with:
         path: ~/.cargo
         key: cargo-home-${{ hashFiles('Cargo.toml') }}
 
     - name: Cache cargo build
-      uses: actions/cache@v2.1.4
+      uses: actions/cache@v2.1.5
       with:
         path: target
         key: wasm-cargo-build-target-${{ hashFiles('Cargo.toml') }}
@@ -138,13 +138,13 @@ jobs:
         components: clippy
 
     - name: Cache CARGO_HOME
-      uses: actions/cache@v2.1.4
+      uses: actions/cache@v2.1.5
       with:
         path: ~/.cargo
         key: cargo-home-${{ hashFiles('Cargo.toml') }}
 
     - name: Cache cargo build
-      uses: actions/cache@v2.1.4
+      uses: actions/cache@v2.1.5
       with:
         path: target
         key: cargo-build-target-${{ hashFiles('Cargo.toml') }}
@@ -170,13 +170,13 @@ jobs:
     - uses: actions/checkout@v2
 
     - name: Cache CARGO_HOME
-      uses: actions/cache@v2.1.4
+      uses: actions/cache@v2.1.5
       with:
         path: ~/.cargo
         key: cargo-home-${{ hashFiles('Cargo.toml') }}
 
     - name: Cache cargo build
-      uses: actions/cache@v2.1.4
+      uses: actions/cache@v2.1.5
       with:
         path: target
         key: cargo-build-target-${{ hashFiles('Cargo.toml') }}