travis: bump gmime depends to 3.0

This is currently unsatisfiable, but at least the build should fail in
a comprehensible way.

diff --git a/.travis.yml b/.travis.yml
index f6d729f233ab0a61775a87cccdc79ff761565d59..90a1cc56137ac4a2543c8ab176ac5e99c21cc257 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,7 +9,7 @@ addons:
     packages:
     - dtach
     - libxapian-dev
-    - libgmime-2.6-dev
+    - libgmime-3.0-dev
     - libtalloc-dev
     - python3-sphinx
     - gpgsm