Update browser versions for sandbox="allow-popups"

This was implemented in WebKit 535.8:
WebKit/WebKit@78f8706
https://github.com/WebKit/WebKit/blob/78f87065d871ddf0bb9d4c77310f62ae6375df47/Source/WebCore/Configurations/Version.xcconfig

That maps to Chrome 17 and Safari 6.

The commit message mentions support in IE10, which is confirmed by this
proposal from the time:
https://www.w3.org/html/wg/wiki/ChangeProposals/sandbox_allow_popups

Thus it must have been in Edge 12 as well.

html/elements/iframe.json

@@ -909,11 +909,11 @@
  "spec_url": "https://html.spec.whatwg.org/multipage/browsers.html#attr-iframe-sandbox-allow-popups",
  "support": {
  "chrome": {
- "version_added": "4"
+ "version_added": "17"
  },
  "chrome_android": "mirror",
  "edge": {
- "version_added": "≤18"
+ "version_added": "12"
  },
  "firefox": {
  "version_added": "28"
@@ -922,13 +922,13 @@
  "version_added": "27"
  },
  "ie": {
- "version_added": null
+ "version_added": "10"
  },
  "oculus": "mirror",
  "opera": "mirror",
  "opera_android": "mirror",
  "safari": {
- "version_added": "≤10.1"
+ "version_added": "6"
  },
  "safari_ios": "mirror",
  "samsunginternet_android": "mirror",