travis: add pry to the dependencies

This is required to run `travis console` but is not part of the upstream
dependency list. Upstream is also not compatible with pry 0.12+ and
breaks with this error `uninitialized constant Pry::SIMPLE_PROMPT`.

Fixes #73238

pkgs/development/tools/misc/travis/Gemfile.lock

@@ -3,13 +3,14 @@ GEM
   specs:
     addressable (2.4.0)
     backports (3.15.0)
+    coderay (1.1.2)
     ethon (0.12.0)
       ffi (>= 1.3.0)
-    faraday (0.15.4)
+    faraday (0.17.0)
       multipart-post (>= 1.2, < 3)
     faraday_middleware (0.13.1)
       faraday (>= 0.7.4, < 1.0)
-    ffi (1.11.1)
+    ffi (1.11.2)
     gh (0.15.1)
       addressable (~> 2.4.0)
       backports
@@ -21,10 +22,14 @@ GEM
     json (2.2.0)
     launchy (2.4.3)
       addressable (~> 2.3)
-    multi_json (1.13.1)
+    method_source (0.9.2)
+    multi_json (1.14.1)
     multipart-post (2.1.1)
     net-http-persistent (2.9.4)
     net-http-pipeline (1.0.1)
+    pry (0.11.3)
+      coderay (~> 1.1.0)
+      method_source (~> 0.9.0)
     pusher-client (0.6.2)
       json
       websocket (~> 1.0)
@@ -45,7 +50,8 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  travis (= 1.8.10)
+  pry (~> 0.11.0)
+  travis
 
 BUNDLED WITH
    1.17.2