fix(pytest): add "-c configfile"

Author: akinomyoga

completions/pytest

@@ -13,11 +13,11 @@ _pytest()
     local cur prev words cword split comp_args
     _comp_initialize -s -n : -- "$@" || return
 
-    local otherflags='!(-*|*[kmorpWn]*)'
+    local otherflags='!(-*|*[kmorpcWn]*)'
     # shellcheck disable=SC2254
     case $prev in
         --help | --maxfail | --report | --junit-prefix | --doctest-glob | \
-            -${otherflags}[hkmorp])
+            -${otherflags}[hkmorpc])
             return
             ;;
         --import-mode)