Contrbuting-Guidelines: remove the unnecessary date (#10)

The date isn't relevant anymore as it is a general guideline now. So, remove it.

Author: sivaraam

android/Contributing-Guidelines.md

@@ -11,7 +11,7 @@ You **must**:
 - Follow correct procedures if adding a new library (additions of new libraries must always be discussed and approved beforehand)
 - Escape HTML tags in strings
 - Write unit tests to cover your own code if you are submitting an enhancement (the issue that you are working on has an "enhancement" label)
-- Follow the [MVP architecture](https://github.com/commons-app/apps-android-commons/issues/888) if you are submitting a large enhancement after 18 March 2019 (definitions of "large" vary according to context - if you are not sure whether this is needed for your code, ask beforehand)
+- Follow the [MVP architecture](https://github.com/commons-app/apps-android-commons/issues/888) if you are submitting a large enhancement (definitions of "large" vary according to context - if you are not sure whether this is needed for your code, ask beforehand)
 
 You should also:
 - Follow the [Google Java Style Guide](https://google.github.io/styleguide/javaguide.html)
@@ -118,4 +118,4 @@ Do not forget to update the [Wiki pages](https://github.com/commons-app/apps-and
 on GitHub to describe the updated behavior and make sure that the resulting
 Wiki pages don't become stale as a consequence of your change.
 
-Note: These guidelines are based on the Git project's [guideline for submitting patches](https://github.com/git/git/blob/master/Documentation/SubmittingPatches). It's licensed under GPLv2.
+Note: These guidelines are based on the Git project's [guideline for submitting patches](https://github.com/git/git/blob/master/Documentation/SubmittingPatches). It's licensed under GPLv2.