1.5.3

Enhancement:

• [libmamba] Backport #2927: Allow defaults::* spec by @isuruf in #2936
• [libmamba] Backport #2921: return architecture levels for micromamba by @isuruf in #2936

Bug fixes:

• [libmamba] Backport #2926: Fix channels with slashes regression by @isuruf in #2936
• [libmambapy] Fix ctrl-c handling issues in libmambapy by @jaimergp in #2946
• [libmamba, libmambapy, mamba] Backport #2949: Parse remote_connect_timeout_secs as a double by @jjerphan in #2951

CI fixes and doc: