ci: temporarily disable Edge because of SauceLabs issues

angular#8604

On Sauce we've been getting the following error:

11 05 2016 00:58:35.765:ERROR [launcher.sauce]: Heartbeat to microsoftedge 20.10240 (Windows 10) failed
  [title()] Error response status: 13, , UnknownError - An unknown server-side error occurred while processing the command. Selenium error: Unknown error (WARNING: The server did not provide any stacktrace information)
Command duration or timeout: 285 milliseconds
Build info: version: '2.52.0', revision: '4c2593c', time: '2016-02-11 19:06:42'
System info: host: 'WIN-SB3ER6JQ6ME', ip: '172.20.60.246', os.name: 'Windows 10', os.arch: 'x86', os.version: '10.0', java.version: '1.8.0_73'
Driver info: org.openqa.selenium.edge.EdgeDriver
Capabilities [{acceptSslCerts=true, browserVersion=25.10586.0.0, platformVersion=10, browserName=MicrosoftEdge, takesScreenshot=true, pageLoadStrategy=normal, takesElementScreenshot=true, platformName=windows, platform=ANY}]
Session ID: XXXXXXXX-XXXX-XXXX-XXXX-XXXX478C1C1A
11 05 2016 00:58:35.766:ERROR [launcher]: microsoftedge 20.10240 (Windows 10) on SauceLabs failed 2 times (failure). Giving up.

browser-providers.conf.js

@@ -12,7 +12,7 @@ var CIconfiguration = {
   'IE9':          { unitTest: {target: 'SL', required: false}, e2e: {target: null, required: true}},
   'IE10':         { unitTest: {target: 'SL', required: true}, e2e: {target: null, required: true}},
   'IE11':         { unitTest: {target: 'SL', required: true}, e2e: {target: null, required: true}},
-  'Edge':         { unitTest: {target: 'SL', required: true}, e2e: {target: null, required: true}},
+  'Edge':         { unitTest: {target: null, required: true}, e2e: {target: null, required: false}},
   'Android4.1':   { unitTest: {target: 'SL', required: false}, e2e: {target: null, required: true}},
   'Android4.2':   { unitTest: {target: 'SL', required: false}, e2e: {target: null, required: true}},
   'Android4.3':   { unitTest: {target: 'SL', required: false}, e2e: {target: null, required: true}},