[gnome-builder] build: bump libpeas dep to 1.21.0

[Christian Hergert <chergert src gnome org>]

commit 2861794ed2cbd85ce807e55ca09d2330406425aa
Author: Christian Hergert <chergert redhat com>
Date:   Fri Jun 9 18:48:27 2017 -0700

    build: bump libpeas dep to 1.21.0
    
    We should have bumped this previously.

 meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index 3de4818..2285b28 100644
--- a/meson.build
+++ b/meson.build
@@ -129,7 +129,7 @@ configure_file(
 libgio_dep = dependency('gio-2.0', version: '>= 2.50.0')
 libgiounix_dep = dependency('gio-unix-2.0')
 libgtk_dep = dependency('gtk+-3.0', version: '>= 3.22.1')
-libpeas_dep = dependency('libpeas-1.0', version: '>= 1.18.0')
+libpeas_dep = dependency('libpeas-1.0', version: '>= 1.21.0')
 libm_dep = cc.find_library('m', required: false)
 libjson_glib_dep = dependency('json-glib-1.0', version: '>= 1.2.0')
 libdazzle_dep = dependency('libdazzle-1.0', version: '>= 0.1.0', required: false)