ci: Don't rebuild cargo-rdme if present

Avoids an error by cargo-install

Author: Techcable

.github/workflows/test.yml

@@ -163,9 +163,11 @@ jobs:
             ~/.cargo/bin/cargo-rdme
           key: ${{ runner.os }}-binary-cargo-rdme
       - name: Install cargo-rdme
+        shell: bash
         run: |
-          cargo install cargo-rdme
+          if not test -f "~/.cargo/bin/cargo-rdme"; then
+            cargo install cargo-rdme
+          fi
       - name: Run cargo-rdme
         run: |
-          cargo install cargo-rdme
           cargo rdme --check