update OpenSSF CII Best Practices badge

OpenSSF CII Best Practices badge is expected to be repository specific.
Our old badge is organization-wide, and does not quality for points
in OpenSSF Scorecard for example.

I've done the CII analysis for IPAM alone, and we have received a
passing badge for IPAM now.

Signed-off-by: Tuomo Tanskanen <tuomo.tanskanen@est.tech>

README.md

@@ -1,7 +1,7 @@
 # Metal3 IP Address Manager for Cluster API Provider Metal3
 
 [![CLOMonitor](https://img.shields.io/endpoint?url=https://clomonitor.io/api/projects/cncf/metal3-io/badge)](https://clomonitor.io/projects/cncf/metal3-io)
-[![OpenSSF Best Practices](https://www.bestpractices.dev/projects/9160/badge)](https://www.bestpractices.dev/projects/9160)
+[![OpenSSF Best Practices](https://www.bestpractices.dev/projects/9968/badge)](https://www.bestpractices.dev/projects/9968)
 [![OpenSSF Scorecard](https://api.securityscorecards.dev/projects/github.com/metal3-io/ip-address-manager/badge)](https://securityscorecards.dev/viewer/?uri=github.com/metal3-io/ip-address-manager)
 [![Ubuntu E2E Integration 1.8 build status](https://jenkins.nordix.org/buildStatus/icon?job=metal3-periodic-ubuntu-e2e-integration-test-release-1-8&subject=Ubuntu%20e2e%20integration%20release-1.8)](https://jenkins.nordix.org/view/Metal3%20Periodic/job/metal3-periodic-ubuntu-e2e-integration-test-release-1-8/)
 [![CentOS E2E Integration release-1.8 build status](https://jenkins.nordix.org/buildStatus/icon?job=metal3-periodic-centos-e2e-integration-test-release-1-8&subject=Centos%20e2e%20integration%20release-1.8)](https://jenkins.nordix.org/view/Metal3%20Periodic/job/metal3-periodic-centos-e2e-integration-test-release-1-8/)