Use Github templates for issues/proposals

Github launched the ability to automatically populate issues and pull requests with custom templates automatically
(https://github.com/blog/2111-issue-and-pull-request-templates). This eliminates the need to have custom scripts
for populating github issues with custom templates. It should be easier for contributors to just open an issue
and not worrying about copy the template.

CONTRIBUTING.md

@@ -45,13 +45,13 @@ Thanks for your contributions!
 
 For very simple contributions - bug fixes, documentation tweaks, small optimizations, etc. - a proposal is not neccesary. Otherwise, it's necessary to discuss your proposal with other members of the community and get approval from the maintainers. 
 
-To create a proposal, copy the markdown from the [proposal template](PROPOSAL_TEMPLATE.md) and put it in the relevant issue. Once you've gotten an LGTM from a [maintainer](MAINTAINERS), you can proceed with putting together a PR.
+To create a proposal, just open a new issue and the template will be automatically populated.
 
 Don't worry if you're proposal is not accepted right away; you'll probably need to make some changes, depending on the scope of the proposal.
 
 Here's a link which creates a new issue populated with the proposal link:
 
-[Create a Proposal](https://github.com/coreos/dex/issues/new?body=Proposal%0A%3D%3D%3D%0A%0A%28Feel%20free%20to%20change%20headings%20here%2C%20remove%20sections%20that%20are%20not%20relevant%2C%20or%20add%20other%20sections%29%0A%0A%23%23%20Background%0A%0ADescribe%20what%20problem%20is%20being%20solved%20here%2C%20and%20%28briefly%29%20how%20this%20proposal%20solves%20it.%0A%0A%23%23%20Data%20Model%0A%0ADescribe%20the%20logical%20data%20model%20that%20your%20proposal%20adds.%0A%0A%23%23%20Data%20Storage%0A%0ADescribe%20how%20the%20data%20will%20be%20persisted.%0A%0A%23%23%20API%0A%0ADescribe%20the%20methods%20that%20the%20API%20will%20expose.%20If%20there%20are%20any%20breaking%20changes%20be%20sure%20to%20call%20them%20out%20here.%0A%0A%23%23%20UI/UX%0A%0AIs%20there%20a%20front-end%20component%20to%20this%20work%3F%0A%0A%23%23%20Implementation%0A%0AHere%20is%20where%20you%20can%20go%20into%20detail%20about%20implementation%20details%20like%20data%20structures%2C%20algorithms%2C%20etc.%0A%0A%23%23%20Security%0A%0AWhat%20are%20the%20security%20implications%20of%20this%20proposal%3F%20How%20are%20API%20requests%20authenticated%3F%20Who%20can%20make%20API%20calls%3F%0A%0A%23%23%20OIDC/OAUTH2%0A%0ADoes%20this%20feature%20relate%20to%20any%20spec%3F%20%0A%0A%23%23%20Risks/Alternatives%20Considered%0A%0AWhat%20are%20the%20downsides%20to%20this%20implementation%3F%20What%20other%20alternatives%20were%20considered%3F%0A%0A%23%23%20References%0A%0AIf%20there%27s%20any%20references%20or%20prior%20art%2C%20put%20that%20here.)
+[Create a Proposal](https://github.com/coreos/dex/issues/new)
 
 ### Format of the Commit Message
 

proposal_link

-#!/bin/bash -e
-
-# This creates a URL which will pre-populate an issue with the contents of PROPOSAL_TEMPLATE.md
-
-BODY=$(python -c "import urllib, sys; print urllib.quote(sys.stdin.read()[0:-1])" < PROPOSAL_TEMPLATE.md)
-
-echo "https://github.com/coreos/dex/issues/new?body=$BODY"