Update Python to 3.7
Update Python to 3.7

Signed-off-by: Tomasz Michalak <a2fdaa543b4cc5e3d6cd8672ec412c0eb393b86e@antmicro.com>

antmicro/litex-rowhammer-tester,antmicro/litex-rowhammer-tester,antmicro/litex-rowhammer-tester