Update cirrus runner to use botan3.

Author: ni4

.cirrus.yml

@@ -32,8 +32,8 @@ task:
   env:
     matrix:
       - { CIRRUS_CLONE_SUBMODULES: true, CRYPTO_BACKEND: openssl, CRYPTO_LIB_INSTALL: openssl, SHARED_LIBS: on,  RNP_LOG_CONSOLE: 1 }
-      - { CIRRUS_CLONE_SUBMODULES: true, CRYPTO_BACKEND: botan,   CRYPTO_LIB_INSTALL: botan2,  SHARED_LIBS: on,  RNP_LOG_CONSOLE: 1 }
-      - { CIRRUS_CLONE_SUBMODULES: true, CRYPTO_BACKEND: botan,   CRYPTO_LIB_INSTALL: botan2,  SHARED_LIBS: off, RNP_LOG_CONSOLE: 1 }
+      - { CIRRUS_CLONE_SUBMODULES: true, CRYPTO_BACKEND: botan,   CRYPTO_LIB_INSTALL: botan3,  SHARED_LIBS: on,  RNP_LOG_CONSOLE: 1 }
+      - { CIRRUS_CLONE_SUBMODULES: true, CRYPTO_BACKEND: botan,   CRYPTO_LIB_INSTALL: botan3,  SHARED_LIBS: off, RNP_LOG_CONSOLE: 1 }
 
   dependencies_script: |
     pkg install -y gcc cmake pkgconf googletest gnupg $CRYPTO_LIB_INSTALL json-c rubygem-asciidoctor