This PR removes the BETA references from mentions of Service Accounts in the README.md file.
It removes the BETA reference from the serviceAccountCredentialId field in the src/main/resources/com/onepassword/jenkins/plugins/config/OnePasswordConfig/config.jelly file.
It specifies that the minimum 1Password CLI version is 2.18.0 to use Service Accounts.
It can be merged after Service Accounts have exited beta and entered general availability (GA).
BETAreferences from mentions of Service Accounts in theREADME.mdfile.BETAreference from theserviceAccountCredentialIdfield in thesrc/main/resources/com/onepassword/jenkins/plugins/config/OnePasswordConfig/config.jellyfile.2.18.0to use Service Accounts.