tools: binman: fix deprecated Python unittest methods

tools: binman: fix deprecated Python unittest methods

The methods `unittest.assertEquals()` and
`unittest.assertRegexpMatches()` are marked deprecated[1].

In Python 3.12 these aliases have been removed, so do a sed to replace
them with their new names.

[1] https://docs.python.org/3.11/library/unittest.html#deprecated-aliases

Signed-off-by: Brandon Maier <brandon.maier@collins.com>
CC: Simon Glass <sjg@chromium.org>
CC: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>