[gimp-web/testing] Add macOS build for GIMP 2.10.12.

[Jehan <jehanp src gnome org>]

commit 73559e60199ab65f5199d7f9ec26b457cfe26bdc
Author: Jehan <jehan girinstud io>
Date:   Thu Jun 13 18:08:45 2019 +0200

    Add macOS build for GIMP 2.10.12.

 GIMP_VERSIONS | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/GIMP_VERSIONS b/GIMP_VERSIONS
index 35523122..a5f1445b 100644
--- a/GIMP_VERSIONS
+++ b/GIMP_VERSIONS
@@ -7,6 +7,13 @@
                         "sha512": 
"dd4af3f0fa6fca815d254b7f42aeff15412c38294f1f5bd491563e2b597fcb868e6adff9001b196a68e01cf49bde61cbb153b662b8da1aa1b4b1f7285879659f",
                         "sha256": "7d80b58e0784120d57d327294f6a1fda281ff51a61935c2cd764da281acaac71"
                 }
+            },
+            "macos": {
+                "gimp-2.10.12-x86_64.dmg": {
+                        "sha512": 
"9feb2450ad73fee8e49b42c4ca1e438f2fc4b3cb1f434e38a88ae7e1f369735236a4fb39a1ccd8d3e5d8c5443b905e6c645d7bc7087c5e6d1ce158a16a8ff61e",
+                        "sha256": "8b964ad3dbbe31d0fa48fb834aa4c17fc0eb81becbc4595a57b04e3d4fc6efeb",
+                        "min-support": "macOS 10.9 Mavericks"
+                }
             }
         },