When using newer PEM format keys (non RSA), I'm getting the following error

that suggest it's the wrong API to get for a variety of keys

and force me to use RSA keys we where considered deprecated in lots of distro by default

```

Failed to launch instance jenkins-oci-builder-10.166.0.5-9a62e2fd-085c-4220-af3b-ff3f78d0ba42 based on template 0 (oci-us-ashburn-1-qa-builder-v1-1)

java.io.IOException: unrecognised object: OPENSSH PRIVATE KEY

at PluginClassLoader for bouncycastle-api//org.bouncycastle.openssl.PEMParser.readObject(Unknown Source)

at PluginClassLoader for oracle-cloud-infrastructure-compute//com.oracle.cloud.baremetal.jenkins.SshKeyUtil.getPublicKey(SshKeyUtil.java:74)

at PluginClassLoader for oracle-cloud-infrastructure-compute//com.oracle.cloud.baremetal.jenkins.BaremetalCloudAgentTemplate.getPublicKey(BaremetalCloudAgentTemplate.java:376)

at PluginClassLoader for oracle-cloud-infrastructure-compute//com.oracle.cloud.baremetal.jenkins.client.SDKBaremetalCloudClient.createInstance(SDKBaremetalCloudClient.java:170)

at PluginClassLoader for oracle-cloud-infrastructure-compute//com.oracle.cloud.baremetal.jenkins.BaremetalCloud.provision(BaremetalCloud.java:244)

at PluginClassLoader for oracle-cloud-infrastructure-compute//com.oracle.cloud.baremetal.jenkins.BaremetalCloud$Provisioner.call(BaremetalCloud.java:232)

at PluginClassLoader for oracle-cloud-infrastructure-compute//com.oracle.cloud.baremetal.jenkins.BaremetalCloud$Provisioner.call(BaremetalCloud.java:207)

at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)

at jenkins.security.ImpersonatingExecutorService$2.call(ImpersonatingExecutorService.java:80)

at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)

at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)

at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)

at java.base/java.lang.Thread.run(Thread.java:1583)

```

Versions:

Oracle Cloud Infrastructure Compute Plugin
Version1.0.18

bouncycastle API
Version2.30.1.81-264.v95c79c0e772c