Clean caches after installing tools

Dockerfile

@@ -20,14 +20,15 @@ RUN \
   echo "${TZ}" > /etc/timezone && date
 
 RUN \
-  go version
-
-RUN \
+  # install golangci-lint
   go get -u -v github.com/golangci/golangci-lint/cmd/golangci-lint@v${GOLANGCI} && \
   go install -ldflags "-X 'main.version=$(git describe --tags)' -X 'main.commit=$(git rev-parse --short HEAD)' -X 'main.date=$(date)'" github.com/golangci/golangci-lint/cmd/golangci-lint && \
-  golangci-lint --version
-
-RUN \
+  # install goswag
   go get -u -v github.com/swaggo/swag/cmd/swag@v${GOSWAG} && \
   go install github.com/swaggo/swag/cmd/swag && \
+  # cleanup
+  go clean -cache -modcache && \
+  # print versions
+  go version && \
+  golangci-lint --version && \
   swag --version