Find the version number

Write a function extractVersion(text) that finds the first version number in a string and returns it. For 'oracle release 12.2c' the answer is '12.2'.

• A version is one or more digits, then zero or more groups of a dot and one or more digits: 19, 12.2, 3.10.4.
• Letters and other characters around the version do not matter: in 'v2.0', '19c' and '4.5-beta1' the versions are '2.0', '19' and '4.5'.
• A dot with no digit right after it is not part of the version: for 'version 12.' return '12'.
• If there are several versions, return the first one.
• Return the version as a string, exactly as it is written in the text ('3.10' stays '3.10', not a number).
• If the text has no digits (or is empty), return null.

A regular expression with match finds the version in one step. Remember that match returns null when nothing is found.