[geary: 1/2] build: Depend on vala >= 0.48.18

[Michael Gratton <mjog src gnome org>]

commit c805f8750c745e7beae5214f828aea94cdffdfd2
Author: Guido Günther <agx sigxcpu org>
Date:   Mon Jul 5 10:19:59 2021 +0200

    build: Depend on vala >= 0.48.18
    
    the `GUri` bindings were added past vala 0.48
    
    ```
    $ git log -1 --pretty=oneline 3c69e297eda4b287a6a37d30d4bf46b83241a453
    3c69e297eda4b287a6a37d30d4bf46b83241a453 glib-2.0: Add GLib.Uri bindings (since 2.66)
    $ git describe 3c69e297eda4b287a6a37d30d4bf46b83241a453
    0.48.2-145-g3c69e297e
    ```
    
    and would require vala 0.50 but the changes were also backported to
    0.48:
    
    $ git log -1 --pretty=oneline e6c95081f8499eda46ca136edcb11b134b58423c
    e6c95081f8499eda46ca136edcb11b134b58423c vapi: Update GLib bindings to 2.66
    $ git describe e6c95081f8499eda46ca136edcb11b134b58423c
    0.48.17-29-ge6c95081f
    
    and are contained in the released 0.48.18.
    
    Closes: #1248

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 233e8c56b..b6a759527 100644
--- a/meson.build
+++ b/meson.build
@@ -55,7 +55,7 @@ valac = meson.get_compiler('vala')
 
 target_glib = '2.66'
 target_gtk = '3.24.23'
-target_vala = '0.48.11'
+target_vala = '0.48.18'
 target_webkit = '2.30'
 
 if not valac.version().version_compare('>=' + target_vala)