NullPointerException if credentialsId isn't specified in http function

[MaxNanasy]

If I do the following:

    library(
      identifier: '<id>@<branch>',
      retriever: http(
        httpURL: '<URL>'
      )
    )

then I get the following exception:

java.lang.NullPointerException
	at java.util.Objects.requireNonNull(Objects.java:203)
	at com.cloudbees.plugins.credentials.CredentialsProvider.findCredentialById(CredentialsProvider.java:872)
	at com.cloudbees.plugins.credentials.CredentialsProvider.findCredentialById(CredentialsProvider.java:850)
	at com.amadeus.jenkins.plugins.workflow.libs.HttpRetriever.initPasswordCredentials(HttpRetriever.java:220)
	at com.amadeus.jenkins.plugins.workflow.libs.HttpRetriever.doRetrieve(HttpRetriever.java:186)
	at com.amadeus.jenkins.plugins.workflow.libs.HttpRetriever.retrieve(HttpRetriever.java:179)
	at org.jenkinsci.plugins.workflow.libs.LibraryAdder.retrieve(LibraryAdder.java:157)
	at org.jenkinsci.plugins.workflow.libs.LibraryStep$Execution.run(LibraryStep.java:207)
	at org.jenkinsci.plugins.workflow.libs.LibraryStep$Execution.run(LibraryStep.java:156)
	at org.jenkinsci.plugins.workflow.steps.AbstractSynchronousNonBlockingStepExecution$1$1.call(AbstractSynchronousNonBlockingStepExecution.java:47)
	at hudson.security.ACL.impersonate(ACL.java:290)
	at org.jenkinsci.plugins.workflow.steps.AbstractSynchronousNonBlockingStepExecution$1.run(AbstractSynchronousNonBlockingStepExecution.java:44)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

Specifying empty credentials works though:

    library(
      identifier: '<id>@<branch>',
      retriever: http(
        httpURL: '<URL>',
        credentialsId: ''
      )
    )