[gimp-web] content: add GIMP 2.99.8 in gimp_versions.json.

[Jehan <jehanp src gnome org>]

commit a6e4aa13a556daa62e79ff8653d16e6a51ebc2f7
Author: Jehan <jehan girinstud io>
Date:   Tue Oct 19 19:54:34 2021 +0200

    content: add GIMP 2.99.8 in gimp_versions.json.
    
    Both source and Windows installer from the same date!
    
    Also it looks like I forgot to add the build-id in the CI rules of GIMP
    build for Windows. So I set it to "Unknown" for this one. This will have
    to be checked and fixed later.

 content/gimp_versions.json | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
---
diff --git a/content/gimp_versions.json b/content/gimp_versions.json
index a3a483bd..fba46897 100644
--- a/content/gimp_versions.json
+++ b/content/gimp_versions.json
@@ -543,6 +543,27 @@
         }
     ],
     "DEVELOPMENT":  [
+        {
+            "version": "2.99.8",
+            "date": "2021-10-19",
+            "source": [
+                {
+                    "filename": "gimp-2.99.8.tar.bz2 ",
+                    "sha512": 
"c603d9a315c21c9da716cc1d8c0c784061e7d0eac4b3d28467aabc3c63c950da0a52649e498049e0b8475933ef93d721a2b8423811b47b00c9490485d316345e",
+                    "sha256": "dd916bd3474ef2efc652a0510280977ab8ea95e3d95d918394b0662261c32aae"
+                }
+            ],
+            "windows": [
+                 {
+                    "date": "2021-10-19",
+                    "filename": "gimp-2.99.8-setup.exe",
+                    "sha512": 
"58f210ae806e91f863ad3c041f55d45f2640a62431c2e2e4706c609a9f78561d3bdad0a9f67f9009e4fa7fd7abe0702b9537ba5c0cc55291888d8a6c1397e052",
+                    "sha256": "c8ba9ad9e9325244042237a4e05ae1e46cc31b0226d287aefcf836e6c8f216db",
+                    "min-support": "Windows 7",
+                    "build-id": "Unknown"
+                }
+            ]
+        },
         {
             "version": "2.99.6",
             "date": "2021-04-26",