Add fixer for Go modules (#1873)

* Add fixer for Go modules

ale_linters/go/govet.vim

@@ -4,20 +4,23 @@
 " Author: John Eikenberry <jae@zhar.net>
 " Description: updated to work with go1.10
 
+call ale#Set('go_go_executable', 'go')
 call ale#Set('go_govet_options', '')
 
 function! ale_linters#go#govet#GetCommand(buffer) abort
     let l:options = ale#Var(a:buffer, 'go_govet_options')
 
-    return ale#path#BufferCdString(a:buffer) . ' go vet .'
+    return ale#path#BufferCdString(a:buffer) . ' '
+    \   . ale#Var(a:buffer, 'go_go_executable') . ' vet '
     \   . (!empty(l:options) ? ' ' . l:options : '')
+    \   . ' .'
 endfunction
 
 call ale#linter#Define('go', {
 \   'name': 'govet',
 \   'aliases': ['go vet'],
 \   'output_stream': 'stderr',
-\   'executable': 'go',
+\   'executable_callback': ale#VarFunc('go_go_executable'),
 \   'command_callback': 'ale_linters#go#govet#GetCommand',
 \   'callback': 'ale#handlers#go#Handler',
 \   'lint_file': 1,