chore(*): update plugin default options && add examples

Signed-off-by: storyicon <yuanchao@bilibili.com>

examples/using-googleapis/README.md

@@ -0,0 +1,29 @@
+# Using Googleapis
+
+This example uses the following public libraries:
+* [googleapis](https://github.com/googleapis/googleapis)
+
+The following plug-ins are used:
+* [protoc-gen-go](google.golang.org/protobuf/cmd/protoc-gen-go)
+* [protoc-gen-go-grpc](google.golang.org/grpc/cmd/protoc-gen-go-grpc)
+* [protoc-gen-grpc-gateway](github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-grpc-gateway)
+
+You can compile the proto file in this directory by executing the following command:
+```
+powerproto build -r ./apis
+```
+
+Not surprisingly, you will get the following output:
+```
+➜ tree
+.
+├── README.md
+├── apis
+│   ├── service.pb.go
+│   ├── service.pb.gw.go
+│   ├── service.proto
+│   └── service_grpc.pb.go
+└── powerproto.yaml
+
+1 directory, 6 files
+```

examples/using-googleapis/apis/service.proto

@@ -0,0 +1,28 @@
+syntax = "proto3";
+
+package powerproto.examples.using_googleapis;
+option go_package = "github.com/storyicon/powerproto/examples/using_googleapis/apis;apis";
+
+import "google/api/annotations.proto";
+
+service Mocker {
+    rpc Echo (EchoRequest) returns (EchoResponse) {
+        option (google.api.http) = {
+            post: "/echo"
+            body: "*"
+        };
+    };
+}
+
+message EchoRequest {
+    string message = 1;
+    int64 timestamp = 2;
+    uint32 code = 3;
+    uint32 delay = 4;
+}
+
+message EchoResponse {
+    string message = 1;
+    int64 timestamp = 2;
+    string server = 3;
+}

examples/using-googleapis/powerproto.yaml

@@ -0,0 +1,25 @@
+scopes:
+    - ./
+protoc: v3.17.3
+protocWorkDir: ""
+plugins:
+    protoc-gen-go: google.golang.org/protobuf/cmd/protoc-gen-go@v1.27.1
+    protoc-gen-go-grpc: google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.1.0
+    protoc-gen-grpc-gateway: github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-grpc-gateway@v2.5.0
+repositories:
+    GOOGLE_APIS: https://github.com/googleapis/googleapis@75e9812478607db997376ccea247dd6928f70f45
+options:
+    - --go_out=.
+    - --go_opt=paths=source_relative
+    - --go-grpc_out=.
+    - --go-grpc_opt=paths=source_relative
+    - --grpc-gateway_out=.
+    - --grpc-gateway_opt=paths=source_relative
+importPaths:
+    - .
+    - $GOPATH
+    - $POWERPROTO_INCLUDE
+    - $SOURCE_RELATIVE
+    - $GOOGLE_APIS/github.com/googleapis/googleapis
+postActions: []
+postShell: ""