chore(evm-rpc): set up GitHub CI (#1028)

This PR updates the GitHub CI on the `evm-rpc-canister` branch to be
equivalent to the original GitLab configuration.

This is a temporary measure to unblock development, since we intend to
migrate this branch into the [EVM RPC
repository](internet-computer-protocol/evm-rpc-canister#252)
(which contains the vast majority of the testing for the forked
codebase).

.github/workflows/evm-rpc.yml

@@ -0,0 +1,19 @@
+name: EVM RPC
+
+on:
+  pull_request:
+
+jobs:
+  build-evm-rpc:
+    name: Build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: nightly
+      - uses: actions-rs/cargo@v1
+        with:
+          command: build
+          args: --package ic-cketh-minter