去除默认的BC加密算法，兼容Android P+

Author: xuzhou

app/src/main/java/org/littleshoot/proxy/mitm/CertificateHelper.java

@@ -255,10 +255,8 @@ private static X509Certificate signCertificate(
             X509v3CertificateBuilder certificateBuilder,
             PrivateKey signedWithPrivateKey) throws OperatorCreationException,
             CertificateException {
-        ContentSigner signer = new JcaContentSignerBuilder(SIGNATURE_ALGORITHM)
-                .setProvider(PROVIDER_NAME).build(signedWithPrivateKey);
-        return new JcaX509CertificateConverter().setProvider(
-                PROVIDER_NAME).getCertificate(certificateBuilder.build(signer));
+        ContentSigner signer = new JcaContentSignerBuilder(SIGNATURE_ALGORITHM).build(signedWithPrivateKey);
+        return new JcaX509CertificateConverter().getCertificate(certificateBuilder.build(signer));
     }
 
     public static TrustManager[] getTrustManagers(KeyStore keyStore)