Fix signature tests

- If the signing key is replaced too fast (within the same second) the
  resolution of OpenPGP timestamps is not good enough to identify the
  sequence of certifications - which might to the selection of the wrong
  signing key.

e2e-tests/tests/60_signing.sh

@@ -41,6 +41,7 @@ else
   exit 1
 fi
 
+sleep 1
 echo "set new signing key"
 
 SIGN_FPR=$($HUSK_BIN --config config/config.toml signkey create | cut -d ':' -f 2 | tr -d ' ')