Add caching for rust core jobs

.github/workflows/ci.yml

@@ -98,6 +98,14 @@ jobs:
           toolchain: ${{ matrix.rust }}
           override: true
 
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+
 #      - name: Check examples
 #        uses: actions-rs/cargo@v1
 #        env:

.github/workflows/leo-clean.yml

@@ -26,6 +26,14 @@ jobs:
           override: true
           components: rustfmt
 
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+
       - name: Install Leo
         uses: actions-rs/cargo@v1
         with:

.github/workflows/leo-init.yml

@@ -26,6 +26,14 @@ jobs:
           override: true
           components: rustfmt
 
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+
       - name: Install Leo
         uses: actions-rs/cargo@v1
         with:

.github/workflows/leo-new.yml

@@ -26,6 +26,14 @@ jobs:
           override: true
           components: rustfmt
 
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+
       - name: Install Leo
         uses: actions-rs/cargo@v1
         with: