How to use public key pinning instead of certificate pinning

Question

I have been using certificate pinning. But now the requirement is to change to public key pinning. I took the project from someone else. I can implement public key pinning using Trustkit. But If I am going to use TrustKit, I have to change a lot of implementations. I have added the code for certificate pinning.

I wanted to use .pinPublicKeys instead of .pinCertificates. But in this implementation, I have to add the certificate to the build, which is what I am trying to avoid. I just want to use the public key hash. For .pinPublicKey, I have to add [secKey]. I couldn't find solutions for converting public hash key to SecKey. Please help with this issue.

class Client {

static let shared = Client()

var manager:SessionManager?

init() {
    let certificates: [SecCertificate] = getCertificates()
    let serverTrustPolicies: [String: ServerTrustPolicy] = [
        "app.###.com": .pinCertificates(
            certificates: certificates,//ServerTrustPolicy.certificates(),
            validateCertificateChain: true,
            validateHost: true
        )
    ]

    manager = Alamofire.SessionManager(
        configuration: URLSessionConfiguration.default,
        serverTrustPolicyManager: ServerTrustPolicyManager(policies: serverTrustPolicies)
    )
}

private func getCertificates() -> [SecCertificate] {
    let url = Bundle.main.url(forResource: "certificate", withExtension: "der")!
    let localCertificate = try! Data(contentsOf: url) as CFData
    guard let certificate = SecCertificateCreateWithData(nil, localCertificate)
       else { return [] }

    return [certificate]
}

}