Update docs theme version to 1.5 #5589

Job	Run time
Build Helm charts	23s
Build and test	9m 1s
Build images	3m 45s
Verify	4m 38s
Verify dependencies	36s
Verify vendorability	1m 9s
Test e2e parallel (with alpha features)	1h 0m 38s
Test e2e parallel	39m 51s
Test e2e serial	26m 21s
Test e2e serial (with alpha features)	30m 38s
All tests successfull	0s
Promote artifacts	0s
Failure notifications	0s
	2h 57m 0s

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