Merge bitcoin/bitcoin#22842: builder-keys: add kristapsk

9d43045b74 builder-keys: add kristapsk (Kristaps Kaupe)

Pull request description:

  https://github.com/bitcoin-core/gitian.sigs/pull/1681#issuecomment-908940489

  This is the key I also use to sign my commits.

  https://keys.openpgp.org/search?q=70A1D47DD44F59DF8B22244333E472FE870C7E5D
  https://github.com/JoinMarket-Org/joinmarket-clientserver/blob/master/pubkeys/KristapsKaupe.asc

ACKs for top commit:
  laanwj:
    ACK 9d43045b74

Tree-SHA512: 151983313c38356828dccb61097a7ce53d6441ac2aa8df7a150f723479187a402e1c05959524748b6d26ac7617d78de8fd7110ec5ba5f32318ac120c602af13b

contrib/builder-keys/keys.txt

@@ -28,6 +28,7 @@ D3CC177286005BB8FF673294C5242A1AB3936517 jl2012 (jl2012)
 32EE5C4C3FA15CCADB46ABE529D4BCB6416F53EC Jonas Schnelli (jonasschnelli)
 4B4E840451149DD7FB0D633477DFAB5C3108B9A8 Jorge Timon (jtimon)
 C42AFF7C61B3E44A1454CD3557AF762DB3353322 Karl-Johan Alm (kallewoof)
+70A1D47DD44F59DF8B22244333E472FE870C7E5D Kristaps Kaupe (kristapsk)
 30DE693AE0DE9E37B3E7EB6BBFF0F67810C1EED1 Lisa Neigut (niftynei)
 E463A93F5F3117EEDE6C7316BD02942421F4889F Luke Dashjr (luke-jr)
 B8B3F1C0E58C15DB6A81D30C3648A882F4316B9B Marco Falke (marco)