Update to gem tilt 2.6.0 (#2345)

Signed-off-by: David A. Wheeler <[email protected]>

Author: david-a-wheeler

Gemfile.lock

@@ -540,7 +540,7 @@ GEM
     terminal-table (1.6.0)
     text (1.3.1)
     thor (1.3.2)
-    tilt (2.5.0)
+    tilt (2.6.0)
     timeout (0.4.3)
     tomlrb (2.0.3)
     translation (1.41)