TYPO: change `bundle.yam` to `bundle.yaml`

[yeskiy]

TYPO: change bundle.yam to bundle.yaml

CHANGE DESCRIPTION

Problem: Simple typo fix in README.md Short explanation of the problem. Change bundle.yam to bundle.yaml in README.md file

[it-percona-cla]

All committers have signed the CLA.

[JNKPercona]

Test name	Status
custom-extensions	passed
custom-tls	passed
demand-backup	passed
finalizers	passed
init-deploy	passed
major-upgrade	failure
monitoring	failure
one-pod	passed
operator-self-healing	passed
pitr	passed
scaling	passed
scheduled-backup	passed
self-healing	passed
start-from-backup	passed
tablespaces	passed
telemetry-transfer	passed
upgrade-consistency	passed
upgrade-minor	passed
users	passed
We run 19 out of 19

commit: https://github.com/percona/percona-postgresql-operator/pull/934/commits/4b15d3a57b9eadb5c4a8391f17ab3266a8237cde image: perconalab/percona-postgresql-operator:PR-934-4b15d3a57

[hors]

@yeskiy thank you for your contribution