Configure aqua to install protoc (#253)

Makefile

@@ -1,3 +1,9 @@
+prepare:
+	curl -sSfL https://raw.githubusercontent.com/aquaproj/aqua-installer/v2.1.1/aqua-installer | bash
+	@echo ''
+	@echo 'Add $${AQUA_ROOT_DIR}/bin to the environment variable PATH.'
+	@echo 'export PATH="$${AQUA_ROOT_DIR:-$${XDG_DATA_HOME:-$$HOME/.local/share}/aquaproj-aqua}/bin:$$PATH"'
+
 proto:
 	cd plugin/proto; \
 	protoc --go_out=. --go_opt=paths=source_relative --go-grpc_out=. --go-grpc_opt=paths=source_relative tflint.proto

README.md

@@ -19,6 +19,26 @@ Please refer to [tflint-ruleset-template](https://github.com/terraform-linters/t
 
 For more details on the API, see [tflint](https://pkg.go.dev/github.com/terraform-linters/tflint-plugin-sdk/tflint) and [helper](https://pkg.go.dev/github.com/terraform-linters/tflint-plugin-sdk/helper) packages on pkg.go.dev.
 
+## Developing
+
+The proto compiler is required when updating `.proto` files. The `protoc` and `protoc-gen-go` can be installed using [aqua](https://github.com/aquaproj/aqua).
+
+```console
+$ make prepare
+curl -sSfL https://raw.githubusercontent.com/aquaproj/aqua-installer/v2.1.1/aqua-installer | bash
+===> Installing aqua v2.2.3 for bootstraping...
+
+...
+
+aqua version 2.3.7 (c07105b10ab825e7f309d2eb83278a0422a2b24f)
+
+Add ${AQUA_ROOT_DIR}/bin to the environment variable PATH.
+export PATH="${AQUA_ROOT_DIR:-${XDG_DATA_HOME:-$HOME/.local/share}/aquaproj-aqua}/bin:$PATH"
+$ export PATH="${AQUA_ROOT_DIR:-${XDG_DATA_HOME:-$HOME/.local/share}/aquaproj-aqua}/bin:$PATH"
+$ aqua install
+$ make proto
+```
+
 ## Architecture
 
 ![architecture](architecture.png)

aqua.yaml

@@ -0,0 +1,15 @@
+---
+# aqua - Declarative CLI Version Manager
+# https://aquaproj.github.io/
+# checksum:
+#   enabled: true
+#   require_checksum: true
+#   supported_envs:
+#   - all
+registries:
+- type: standard
+  ref: v3.159.0 # renovate: depName=aquaproj/aqua-registry
+packages:
+- name: protocolbuffers/protobuf/[email protected]
+- name: protocolbuffers/protobuf-go/[email protected]
+- name: grpc/grpc-go/protoc-gen-go-grpc@cmd/protoc-gen-go-grpc/v1.3.0