REGTESTS: jwt: Add tests for the jwt_verify converter

This regtest uses the new jwt_header_query, jwt_payload_query and
jwt_verify converters that can be used to validate a JSON Web Token.
diff --git a/reg-tests/jwt/es256-public.pem b/reg-tests/jwt/es256-public.pem
new file mode 100644
index 0000000..ac69e6d
--- /dev/null
+++ b/reg-tests/jwt/es256-public.pem
@@ -0,0 +1,4 @@
+-----BEGIN PUBLIC KEY-----
+MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEjq7vv/FURryqr7ukvkrn1ek5rjCM
+hOngjD17uQTZN7fo1QRIV18lPx5O2Ed5ok/j8j/hZaFOB6TNshNmthk3dA==
+-----END PUBLIC KEY-----