merge: fix package option parse error

refer: lervag#3184

Author: lervag

autoload/vimtex/state/class.vim

@@ -328,7 +328,9 @@ function! s:parse_optionlist(string) abort " {{{1
       continue
     elseif l:element =~# '='
       " Key-value option
-      let [l:key, l:value] = map(split(l:element, '='), {_, x -> trim(x)})
+      let [l:key, l:value] = map(
+            \ split(l:element, '=', v:true),
+            \ {_, x -> trim(x)})
 
       if l:value ==? 'true'
         let l:options[l:key] = v:true

test/test-state/test_parse_package_options.tex

@@ -5,6 +5,7 @@
 
 \usepackage[acronyms]{glossaries}
 \usepackage[record,style=long]{glossaries-extra}
+\usepackage[key=]{package}
 
 \usepackage[% comment
   backend=biber,

test/test-state/test_parse_package_options.vim

@@ -26,7 +26,8 @@ let s:packages = {
       \ 'package1': {'draft': v:true},
       \ 'biblatex-chicago': {'notes': v:true, 'useibid': v:true},
       \ 'amsmath': {},
-      \ 'package2': {'draft': v:true}
+      \ 'package2': {'draft': v:true},
+      \ 'package': {'key': ''}
       \ }
 call assert_equal(s:packages, b:vimtex.packages)