doc: New ISSUE Template for Request Security issues

.github/ISSUE_TEMPLATE.md

 <!--
 
-**Do not ask to but Request package, it breaks old Node compatiblity. It is used for downloading the binaries.**
-
 Before opening an issue:
 - Check that the version of node-sass you're trying to install supports your version of Node by looking at the release page for that version https://github.com/sass/node-sass/releases
 - Read the common workarounds in the [TROUBLESHOOTING.md](https://github.com/sass/node-sass/blob/master/TROUBLESHOOTING.md)

.github/ISSUE_TEMPLATE/Request_Security.md

+# Please do not open an issue
+
+See https://github.com/sass/node-sass/issues/2355 for the reason we can't upgrade the Request version that your security scanner is flagging.