Update version number to 3.8.0-RC1
Update version number to 3.8.0-RC1

ndm2/cakephp,dakota/cakephp,ADmad/cakephp,ndm2/cakephp,cakephp/cakephp,dakota/cakephp,dakota/cakephp,mvdriel/cakephp,CakeDC/cakephp,ndm2/cakephp,mvdriel/cakephp,mvdriel/cakephp,CakeDC/cakephp,ndm2/cakephp,ADmad/cakephp,dakota/cakephp,CakeDC/cakephp,cakephp/cakephp,CakeDC/cakephp,ADmad/cakephp,mvdriel/cakephp,cakephp/cakephp,cakephp/cakephp,ADmad/cakephp