feat: add justfile (#210)

file with helper commands for testing and prepping PRs for the repo

ie run `just prep` to fix lint and generate updated snapshots

justfile

@@ -0,0 +1,30 @@
+test: test-forge test-hardhat
+prep: fix snapshots
+snapshots: snapshots-forge snapshots-hardhat
+
+test-forge: install-forge build-forge
+    forge test
+
+test-hardhat: install-hardhat
+    yarn test
+
+build-forge: install-forge
+    forge build
+
+build-hardhat: install-hardhat
+    yarn build
+
+snapshots-forge: install-forge
+    forge snapshot
+
+snapshots-hardhat: install-hardhat
+    yarn snapshots
+
+install-forge:
+    forge install
+
+install-hardhat:
+    yarn install
+
+fix:
+    forge fmt