docs: add public key to readme

Author: d-perl

README.md

@@ -2,4 +2,23 @@
 
 [![Linting](https://github.com/bec-project/bec_log_ingestor/actions/workflows/check-and-lint.yaml/badge.svg)](https://github.com/bec-project/bec_log_ingestor/actions/workflows/check-and-lint.yaml) [![codecov](https://codecov.io/gh/bec-project/bec_log_ingestor/graph/badge.svg?token=B7Mzj4EhzH)](https://codecov.io/gh/bec-project/bec_log_ingestor)
 
-Tiny service to pull BEC logs from Redis and push them to Elastic
+Tiny service to pull BEC logs from Redis and push them to Elastic.
+
+Published RPM packages are signed by PGP, the corresponding public key is:
+
+```
+-----BEGIN PGP PUBLIC KEY BLOCK-----
+
+mDMEaONxxBYJKwYBBAHaRw8BAQdA/Y2oM4wF9kWCHh871tRVkpXD43Kwcv+4hawF
+KXSU8wW0NkJFQyBUZWFtIChCRUMgUlBNIHNpZ25pbmcga2V5KSA8YmVjX2NpX3N0
+YWdpbmdAcHNpLmNoPoiWBBMWCgA+FiEEzj2vq2b33XAPoA97EO1Yp4CfPg4FAmjj
+ccQCGwMFCQHhM4AFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AACgkQEO1Yp4CfPg5H
+SQEAxH518nANNuBhiNaWQrcfG0M8MsNv0MPmw8KIu2av3wQBAOTnnx+KSMz3G3FV
+pXWNXqodA3hevPmlEGK3p9246DQHuDgEaONxxBIKKwYBBAGXVQEFAQEHQCD0FdIe
+KMARufv8f1q1UpHe/VezH5ws0FWyea6b7ow5AwEIB4h+BBgWCgAmFiEEzj2vq2b3
+3XAPoA97EO1Yp4CfPg4FAmjjccQCGwwFCQHhM4AACgkQEO1Yp4CfPg4mkwD9GR4+
+hFUtIZhCUdQB3ttwcW7TRKF98zthyA+LU+/YDsMBAMXjE/ZlZVgTmKk6tMamLF1R
+cX0DclDjhPJgOxT6NZwB
+=ATUU
+-----END PGP PUBLIC KEY BLOCK-----
+```