meson.build: Require at least meson 0.50.0

The `install` argument in `configure_file` is a feature introduced in
meson '0.50.0', but meson.build requests '>=0.47.0'. Meson complains:

 WARNING: Project targeting '>=0.47.0' but tried to use feature
          introduced in '0.50.0': install arg in configure_file.

To correct this, adjust the `meson_version` value accordingly.

Change-Id: Iadcffb7f8c720ffa8aa5f0ad62638d7b37f39934
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/49924
Original-Reviewed-by: Sam McNally <sammc@google.com>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/71762
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/meson.build b/meson.build
index b2ee0e3..e872263 100644
--- a/meson.build
+++ b/meson.build
@@ -1,7 +1,7 @@
 project('flashromutils', 'c',
   version : run_command('util/getversion.sh', '-v').stdout().strip(),
   license : 'GPL-2.0',
-  meson_version : '>=0.47.0',
+  meson_version : '>=0.50.0',
   default_options : ['warning_level=2', 'c_std=c99'],
 )