Fix typo (nektos#685)

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

README.md

@@ -138,7 +138,7 @@ It will save that information to `~/.actrc`, please refer to [Configuration](#co
       --detect-event                    Use first event type from workflow as event that triggered the workflow
   -C, --directory string                working directory (default ".")
   -n, --dryrun                          dryrun mode
-      --env stringArray                 env to make available to actions with optional value (e.g. --e myenv=foo or -s myenv)
+      --env stringArray                 env to make available to actions with optional value (e.g. --env myenv=foo or -s myenv)
       --env-file string                 environment file to read and use as env in the containers (default ".env")
   -e, --eventpath string                path to event JSON file
       --github-instance string          GitHub instance to use. Don't use this if you are not using GitHub Enterprise Server. (default "github.com")