Add PULL_REQUEST_TEMPLATE.md
Add PULL_REQUEST_TEMPLATE.md

Change-Id: Icb670c70d3afbf3b1476a5968ab8f3f910e0000f
Signed-off-by: David Enyeart <3d699cfec69cc11a9ba1c3a1aef3260ab163489b@us.ibm.com>

muralisrini/fabric,binhn/fabric,stemlending/fabric,manish-sethi/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,hyperledger/fabric,hyperledger/fabric,jimthematrix/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,muralisrini/fabric,binhn/fabric,binhn/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,stemlending/fabric,muralisrini/fabric,stemlending/fabric,jimthematrix/fabric,stemlending/fabric,manish-sethi/fabric