test: go: Generate new RSA key

The old one complains about invalid modulus with new Go.
Related to golang/go#70643 maybe?

Author: KoviRobi

smtp/server_dkim_test.go

@@ -18,19 +18,19 @@ import (
 )
 
 const testPrivateKeyPEM = `-----BEGIN RSA PRIVATE KEY-----
-MIICXwIBAAKBgQDwIRP/UC3SBsEmGqZ9ZJW3/DkMoGeLnQg1fWn7/zYtIxN2SnFC
-jxOCKG9v3b4jYfcTNh5ijSsq631uBItLa7od+v/RtdC2UzJ1lWT947qR+Rcac2gb
-to/NMqJ0fzfVjH4OuKhitdY9tf6mcwGjaNBcWToIMmPSPDdQPNUYckcQ2QIDAQAB
-AoGBALmn+XwWk7akvkUlqb+dOxyLB9i5VBVfje89Teolwc9YJT36BGN/l4e0l6QX
-/1//6DWUTB3KI6wFcm7TWJcxbS0tcKZX7FsJvUz1SbQnkS54DJck1EZO/BLa5ckJ
-gAYIaqlA9C0ZwM6i58lLlPadX/rtHb7pWzeNcZHjKrjM461ZAkEA+itss2nRlmyO
-n1/5yDyCluST4dQfO8kAB3toSEVc7DeFeDhnC1mZdjASZNvdHS4gbLIA1hUGEF9m
-3hKsGUMMPwJBAPW5v/U+AWTADFCS22t72NUurgzeAbzb1HWMqO4y4+9Hpjk5wvL/
-eVYizyuce3/fGke7aRYw/ADKygMJdW8H/OcCQQDz5OQb4j2QDpPZc0Nc4QlbvMsj
-7p7otWRO5xRa6SzXqqV3+F0VpqvDmshEBkoCydaYwc2o6WQ5EBmExeV8124XAkEA
-qZzGsIxVP+sEVRWZmW6KNFSdVUpk3qzK0Tz/WjQMe5z0UunY9Ax9/4PVhp/j61bf
-eAYXunajbBSOLlx4D+TunwJBANkPI5S9iylsbLs6NkaMHV6k5ioHBBmgCak95JGX
-GMot/L2x0IYyMLAz6oLWh2hm7zwtb0CgOrPo1ke44hFYnfc=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 -----END RSA PRIVATE KEY-----
 `