update issue templates

Add checkbox whether user had read our contributing guide,
specifically the "note about package requests".

.github/ISSUE_TEMPLATE/package_request.md

@@ -9,18 +9,12 @@ IMPORTANT: we are not accepting issues about Termux
 installations running on Android 5.x-6.x.
 -->
 
-<!--
-Note that requests for packages that can be installed through 
-other package managers (like python's pip, ruby's gem, nodejs's 
-npm, ..) generally are closed and users are refered to use the 
-other package manager.
--->
+- [ ] I have read [Termux policy on package requests](/CONTRIBUTING.md#a-note-about-package-requests).
 
 **Package description**
 <!--
 Describe what this package do and why it should be
-available. Make sure that requested package supports
-cross-compilation and can run on AArch64 and ARM.
+available.
 -->
 
 **Link to home page and sources**
@@ -30,4 +24,4 @@ cross-compilation and can run on AArch64 and ARM.
 **Additional information**
 Have you compiled or tried to compile the package on device?
 * If it did not work then please provide the error you ran into.
-* If it did work then please share any patches that you had to apply.
+* If it did work then please share build steps and any patches that you had to apply.