fix: skip open in ci

Author: zimeg

scripts/generate_api_docs.sh

@@ -1,8 +1,8 @@
 #!/bin/bash
 # Generate API documents from the latest source code
 
-script_dir=`dirname $0`
-cd ${script_dir}/..
+script_dir=$(dirname "$0")
+cd "${script_dir}"/.. || exit
 
 pip install -U -r requirements/documentation.txt
 pip install -U -r requirements/optional.txt
@@ -13,4 +13,6 @@ pdoc slack_sdk --html -o docs/reference
 cp -R docs/reference/slack_sdk/* docs/reference/
 rm -rf docs/reference/slack_sdk
 
-open docs/reference/index.html
+if [[ -z "${CI:-}" ]]; then
+    open docs/reference/index.html
+fi