.github/workflows: fix modules mode tools installation

By installing all tools in one `go get` command, we ended up building
tools different from the intended versions. Nightly release was broken
because when building gopls, we picked up more recent `golang.org/x/tools`
as a dependency becuase some other tools installed together influenced
the version choice.

The recent version of `golang.org/x/tools` includes a change that
causes gopls to return unexpected results until its internal state
gets stablized. That broke our completion item test.

This CL changes tool installation to match other CI workflows.

We will need a test to use the master version of gopls but in a way
that doesn't block our releases.

Fixes golang/vscode-go#363

Change-Id: Ia8558a0e7e6f298a9a6a5e57b24d356974b3a460
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/243639
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
diff --git a/.github/workflows/release-nightly.yml b/.github/workflows/release-nightly.yml
index 8110c20..0df894b 100644
--- a/.github/workflows/release-nightly.yml
+++ b/.github/workflows/release-nightly.yml
@@ -40,34 +40,34 @@
       - name: Compile
         run: npm run vscode:prepublish
+      # TODO: use prerelease versions of tools (how? or master?)
       - name: Install Go tools (Modules mode)
         run: |
             go version
-            go get github.com/acroca/go-symbols \
-               github.com/davidrjenni/reftools/cmd/fillstruct \
-               github.com/haya14busa/goplay/cmd/goplay \
-               github.com/mdempsky/gocode \
-               github.com/sqs/goreturns \
-               github.com/uudashr/gopkgs/v2/cmd/gopkgs \
-               github.com/zmb3/gogetdoc \
-               golang.org/x/lint/golint \
-               golang.org/x/tools/cmd/gorename \
-               golang.org/x/tools/gopls
+            go get github.com/acroca/go-symbols
+            go get github.com/davidrjenni/reftools/cmd/fillstruct
+            go get github.com/haya14busa/goplay/cmd/goplay
+            go get github.com/mdempsky/gocode
+            go get github.com/sqs/goreturns
+            go get github.com/uudashr/gopkgs/v2/cmd/gopkgs
+            go get github.com/zmb3/gogetdoc
+            go get golang.org/x/lint/golint
+            go get golang.org/x/tools/cmd/gorename
+            go get golang.org/x/tools/gopls
-          GO111MODULE: on
+          GO111MODULE: on   
       - name: Install Go tools (GOPATH mode)
         run: |
           go version
-          go get github.com/cweill/gotests/... \
-            github.com/rogpeppe/godef \
-            github.com/ramya-rao-a/go-outline
+          go get github.com/cweill/gotests/...
+          go get github.com/rogpeppe/godef
+          go get github.com/ramya-rao-a/go-outline
             # Because some tests depend on the source code checked in GOPATH. TODO: FIX THEM.
           GO111MODULE: off
       - name: Run unit tests
         run: npm run unit-test