Revert "Pin down versions so hop can run on drone.io"

This reverts commit c8dd283.

pubspec.yaml

@@ -4,13 +4,7 @@ version: 0.9.7
 author: John McCutchan <john@johnmccutchan.com>
 homepage: https://github.com/johnmccutchan/DartVectorMath
 dependencies:
-  unittest: '>=0.4.1 <0.4.2'
-  browser: '>=0.4.1 <0.4.2'
-  bot: '>=0.15.0 <0.16.0'
-  meta: '>=0.4.1 <0.4.2'
-  html5lib: '>=0.4.0 <0.4.1'
-  args: '>=0.4.1 <0.4.2'
-  logging: '>=0.4.1 <0.4.2'
-  pathos: '>=0.4.1 <0.4.2'
-  source_maps: '>=0.4.0 <0.4.1'
+  browser: any
+  unittest: any
+  bot: ">=0.15.0"