Fix install sh usage (#2454)

* Note that godownloader is deprecated

* Fix usage

* Fix spelling of install

---------

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

install.sh

@@ -1,23 +1,20 @@
 #!/bin/sh
 set -e
-# Code generated by godownloader on 2021-12-22T16:10:52Z. DO NOT EDIT.
+# Code originally generated by godownloader on 2021-12-22T16:10:52Z. DO NOT EDIT.
+# (godownloader is deprecated, so changes to this script are maintained in install.sh in https://github.com/nektos/act)
 #
 
 usage() {
   this=$1
   cat <<EOF
 $this: download go binaries for nektos/act
 
-Usage: $this [-b] bindir [-d] [tag]
+Usage: $this [-b bindir] [-d] [tag]
   -b sets bindir or installation directory, Defaults to ./bin
   -d turns on debug logging
    [tag] is a tag from
    https://github.com/nektos/act/releases
    If tag is missing, then the latest will be used.
-
- Generated by godownloader
-  https://github.com/goreleaser/godownloader
-
 EOF
   exit 2
 }