Update docker compose command to V2 (#950)

Update docker compose command to V2 in accordance of deprecation of docker-compose V1 on GitHub Actions runner's ubuntu image.

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
       run: make build
 
     - name: Stack
-      run: docker-compose -f build/docker/docker-compose.yml up --build -d
+      run: docker compose -f build/docker/docker-compose.yml up --build -d
 
     - name: Test
       run: go test -tags integration -race -coverprofile=coverage.txt -covermode=atomic -v ./...
@@ -77,7 +77,7 @@ jobs:
       run: make tools
 
     - name: Stack
-      run: docker-compose -f build/docker/docker-compose.yml up --build -d
+      run: docker compose -f build/docker/docker-compose.yml up --build -d
 
     - name: Bench
       run: make bench

CONTRIBUTING.md

@@ -48,7 +48,7 @@ make build		# executable: ./bin/yorkie
 You can set testing environment via Docker Compose. It is needed because integration tests require local applications like MongoDB.
 
 ```sh
-docker-compose -f build/docker/docker-compose.yml up --build -d
+docker compose -f build/docker/docker-compose.yml up --build -d
 make test
 ```
 

build/docker/README.md

@@ -5,14 +5,14 @@ running multi-container Docker applications. We use Docker Compose to run the
 applications needed during Yorkie development.
 
 When developing Yorkie, we can easily run the required dependant applications
-through `docker-compose` command.
+through `docker compose` command.
 
 ```bash
-# Run docker-compose up and Compose starts and runs apps.
-docker-compose -f docker/docker-compose.yml up --build -d
+# Run docker compose up and Compose starts and runs apps.
+docker compose -f docker/docker-compose.yml up --build -d
 
 # Shut down the apps
-docker-compose -f docker/docker-compose.yml down
+docker compose -f docker/docker-compose.yml down
 ```
 
 The docker-compose files we use are as follows: