Update signatories

Author: marcprux

src/data/signatures.yaml

@@ -25,6 +25,9 @@
 - organization: "Digital Rights Watch"
   url: "digitalrightswatch.org.au"
   poc: "Tom Sulston <tom@digitalrightswatch.org.au>"
+- organization: "Ente"
+  url: "ente.io"
+  poc: "Vishnu Mohandas <vishnu@ente.io>"
 - organization: "epicenter.works – for digital rights"
   url: "epicenter.works"
   poc: "Thomas Lohninger <thomas.lohninger@epicenter.works>"
@@ -79,6 +82,9 @@
 - organization: "Tuta Mail"
   url: "tutao.de"
   poc: "Hanna Bozakov <hanna.bozakov@tutao.de>"
+- organization: "Vivaldi"
+  url: "vivaldi.com"
+  poc: "Jon von Tetzchner <jon@vivaldi.com>"
 
 #- organization: "XXX"
 #  url: "XXX"