chore: refactor build process and update .gitignore

- Add `bin/` to the `.gitignore` file
- Move the build output to the `bin/` directory in the `Makefile`

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

.gitignore

@@ -15,3 +15,4 @@
 
 drone-lambda
 coverage.txt
+bin/

Makefile

@@ -81,19 +81,19 @@ install: $(GOFILES)
 build: $(EXECUTABLE)
 
 $(EXECUTABLE): $(GOFILES)
-	$(GO) build -v -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o $@
+	$(GO) build -v -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o bin/$@
 
 build_linux_amd64:
-	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 $(GO) build -a -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o release/linux/amd64/$(DEPLOY_IMAGE)
+	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 $(GO) build -a -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o release/linux/amd64/$(EXECUTABLE)
 
 build_linux_i386:
-	CGO_ENABLED=0 GOOS=linux GOARCH=386 $(GO) build -a -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o release/linux/i386/$(DEPLOY_IMAGE)
+	CGO_ENABLED=0 GOOS=linux GOARCH=386 $(GO) build -a -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o release/linux/i386/$(EXECUTABLE)
 
 build_linux_arm64:
-	CGO_ENABLED=0 GOOS=linux GOARCH=arm64 $(GO) build -a -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o release/linux/arm64/$(DEPLOY_IMAGE)
+	CGO_ENABLED=0 GOOS=linux GOARCH=arm64 $(GO) build -a -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o release/linux/arm64/$(EXECUTABLE)
 
 build_linux_arm:
-	CGO_ENABLED=0 GOOS=linux GOARCH=arm GOARM=7 $(GO) build -a -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o release/linux/arm/$(DEPLOY_IMAGE)
+	CGO_ENABLED=0 GOOS=linux GOARCH=arm GOARM=7 $(GO) build -a -tags '$(TAGS)' -ldflags '$(EXTLDFLAGS)-s -w $(LDFLAGS)' -o release/linux/arm/$(EXECUTABLE)
 
 coverage:
 	sed -i '/main.go/d' coverage.txt