escape ` (#111)

gh-act

@@ -191,6 +191,7 @@ function parts_json {
 }
 
 function filter_envs {
+    # shellcheck disable=SC2016
     sed -e '/^$/d' \
         -e 's/<no value>/null/g' \
         -e "s/\\\\'/'/g" \
@@ -201,7 +202,8 @@ function filter_envs {
         -e 's/\\u003D/=/g' \
         -e 's/\\u003E/>/g' \
         -e 's/\\/\\\\/g' \
-        -e 's/\\"/\\\\\"/g'
+        -e 's/\\"/\\\\\"/g' \
+        -e 's/`/\\`/g'
 }
 
 function is_valid_user {
@@ -447,7 +449,7 @@ function pull_request_event_envs() {
 
     # shellcheck disable=SC2086
     BEFORE=$(gh pr view "${PULL_REQUEST_SPEC}" --json commits --jq .commits[].oid | tail -2 | head -1)
-    # shellcheck disable=SC2046
+    # shellcheck disable=SC2016,SC2046
     read -r HEAD HEAD_USER <<< $(gh pr view "${PULL_REQUEST_SPEC}" --json commits \
         --template '{{- $last := 0}}
 {{- range $index, $element := .commits}}{{$last = $index}}{{end}}