Removing -u option from Makefile and README (relies too heavily on stable dependencies) (#22)

Co-authored-by: chrusty <prawn@localhost>

Author: chrusty

Makefile

@@ -6,7 +6,7 @@ build:
 	@go build -o bin/protoc-gen-jsonschema cmd/protoc-gen-jsonschema/main.go
 
 install:
-	@GO111MODULE=on go get -u github.com/chrusty/protoc-gen-jsonschema/cmd/protoc-gen-jsonschema && go install github.com/chrusty/protoc-gen-jsonschema/cmd/protoc-gen-jsonschema
+	@GO111MODULE=on go get github.com/chrusty/protoc-gen-jsonschema/cmd/protoc-gen-jsonschema && go install github.com/chrusty/protoc-gen-jsonschema/cmd/protoc-gen-jsonschema
 
 build_linux:
 	@echo "Generating Linux-amd64 binary (protoc-gen-jsonschema.linux-amd64) ..."

README.md

@@ -9,7 +9,7 @@ This will hopefully be useful for people who define their data using ProtoBuf, b
 
 Installation
 ------------
-`GO111MODULE=on go get -u github.com/chrusty/protoc-gen-jsonschema/cmd/protoc-gen-jsonschema && go install github.com/chrusty/protoc-gen-jsonschema/cmd/protoc-gen-jsonschema`
+`GO111MODULE=on go get github.com/chrusty/protoc-gen-jsonschema/cmd/protoc-gen-jsonschema && go install github.com/chrusty/protoc-gen-jsonschema/cmd/protoc-gen-jsonschema`
 
 Links
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