Revision.tag field is not trimmed before insert

[quasilyte]

Seems like release tags are not truncated before insertion.
This is a trouble for git integration as it inserts tags with a trailing newline:

SELECT tag FROM codespeed_revision WHERE tag like 'go1.7%';
-- =>
-- "go1.7
-- "
-- "go1.7.1
-- "
-- "go1.7.2
-- "
-- "go1.7.3
-- "
-- "go1.7.4
-- "
-- "go1.7.5
-- "
-- "go1.7.6
-- "

So, query like this will return nothing:

SELECT tag FROM codespeed_revision WHERE tag = 'go1.7';
-- =>
-- No results

But this query will find desired row:

SELECT tag FROM codespeed_revision WHERE tag = E'go1.7\n';
-- =>
-- "go1.7
-- "

This may have several workarounds, but it's still better to store trimmed tags.
Leading and trailing whitespace should not be significant here.

Or maybe git log parser could trim tag string, this way, no changes to models are required (if we are sure that there are no similar issues with other VSC).

codespeed/codespeed/commits/git.py

Line 94 in 784bdfc

'tag': tag

-  'tag': tag
+  'tag': tag.strip()

For extra context: I'm using postgresql for Codespeed database.