Only build FSharpLanguageServer

Before this commit, we would needlessly be building everything,
including unit tests. By only building what we need, we speed up the
process a bit and make it slightly more robust in case tests don't build
(which, coincidentally, they do not at the time of writing).

Author: ibsenrune

installer/install-fsharp-language-server.sh

@@ -4,7 +4,9 @@ set -e
 
 git clone --depth=1 https://github.com/fsprojects/fsharp-language-server .
 npm install
-dotnet publish --configuration Release --output Publish
+dotnet tool install --global paket
+dotnet tool restore
+dotnet publish src/FSharpLanguageServer --configuration Release --output Publish 
 
 cat <<EOF >fsharp-language-server
 #!/bin/sh