tools: upgrade tools

Author: zchee

tools/go.mod

@@ -3,8 +3,8 @@ module go.lsp.dev/protocol/tools
 go 1.15
 
 require (
-	github.com/golangci/golangci-lint v1.37.1
-	golang.org/x/tools v0.1.1-0.20210222153519-0e232fa9c3bc
-	gotest.tools/gotestsum v1.6.2
-	mvdan.cc/gofumpt v0.1.0
+	github.com/golangci/golangci-lint v1.39.0
+	golang.org/x/tools v0.1.1-0.20210415232134-cb5dc85ca1a7
+	gotest.tools/gotestsum v1.6.3
+	mvdan.cc/gofumpt v0.1.1
 )