Raise minimal grpcio-tools version to fix missing protobuf upperbound (#684)

* Raise minimal grpcio-tools version to fix missing protobuf upperbound

[ML-10393](https://iguazio.atlassian.net/browse/ML-10393)

* Delete impi

Author: gtopper

Makefile

@@ -140,31 +140,5 @@ else
 	$(error Please run `go fmt ./...` to format the code)
 endif
 
-.PHONY: impi
-impi:
-	@echo Installing impi...
-	GO111MODULE=off go get -u github.com/pavius/impi/cmd/impi
-	@echo Verifying imports...
-	$(GOPATH)/bin/impi \
-		--local github.com/iguazio/provazio \
-		--skip pkg/controller/apis \
-		--skip pkg/controller/client \
-		--ignore-generated \
-		--scheme stdLocalThirdParty \
-		./...
-
-$(GOPATH)/bin/golangci-lint:
-	@echo Installing golangci-lint...
-	curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s v1.49.0
-	cp ./bin/golangci-lint $(GOPATH)/bin/
-
 .PHONY: lint
-lint: gofmt impi $(GOPATH)/bin/golangci-lint
-	@echo Linting...
-	@$(GOPATH)/bin/golangci-lint run \
-     --disable-all --enable=deadcode --enable=goconst --enable=golint --enable=ineffassign \
-     --enable=interfacer --enable=unconvert --enable=varcheck --enable=errcheck --enable=gofmt --enable=misspell \
-     --enable=staticcheck --enable=gosimple --enable=govet --enable=goconst \
-     --timeout=10m \
-    api/... backends/... cmd/... framulate/... grpc/... http/... repeatingtask/... v3ioutils/...
-	@echo done linting
+lint: gofmt

clients/py/requirements.txt

@@ -1,7 +1,8 @@
 googleapis-common-protos>=1.5.3
 # grpcio-tools 1.34.0 must not be used as it segfaults (1.34.1 ok).
 # grpcio-tools 1.49 raises protobuf version from 3.x to 4.x, which breaks compatibility.
-grpcio-tools>=1.30,!=1.34.0,<1.49
+# grpcio-tools 1.30.0 lacks a protobuf upperbound, which was added in 1.31.0
+grpcio-tools>=1.31,!=1.34.0,<1.49
 protobuf<4
 pandas>=0.23.4
 requests>=2.19.1