Bump actions/attest-build-provenance from 1 to 2 #3549

Job	Run time
check_branch	1s
Build Openfire from source (17, zulu)	4m 1s
Check if database upgrade tests should be run	3s
Build Openfire from source (21, zulu)	4m 3s
Execute aioxmpp-based CI tests	2m 2s
Execute Smack-based CI tests	56s
Generate DEB artifact	9m 8s
Execute Connectivity CI tests	28s
Test MySQL Upgrades	1m 17s
Test Postgres Upgrades	1m 5s
Test SQL Server Upgrades	1m 8s
Publish to GitHub's Docker registry	0s
Publish to Maven	0s
	24m 12s

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