Ask for "go env" (#1547)

This gives us GOPATH and such, as well as OS info. Also word things
stronger that people *must* fill this out.

.github/ISSUE_TEMPLATE.md

@@ -1,15 +1,22 @@
 ### What did you do? (required. The issue will be **closed** when not provided.)
 
-Please provide a recipe to replicate your problem with a minimal `vimrc` with all plugins other than vim-go disabled.
 
 ### What did you expect to happen?
 
+
 ### What happened instead?
 
-### Configuration
 
-* vim version (major, minor, and included patches from `:version`):
+### Configuration (**MUST** fill this out):
+
+* Vim version (first two lines from `:version`):
+
+* Go version (`go version`):
+
+* Go environment (`go env`):
+
 * vim-go version:
-* go version (`go version`):
-* operating system:
-* `vimrc` you used to reproduce:
+
+* `vimrc` you used to reproduce (use a *minimal* vimrc with other plugins disabled; do not link to a 2,000 line vimrc):
+
+