chore: update version references to v2.12.0, remove RCs (#144)

Author: pfeerick

targets.json

@@ -3,16 +3,7 @@
     "nightly": {
       "sem_ver": "v3.0.0"
     },
-    "v2.12.0-rc4": {
-      "build_container": "ghcr.io/edgetx/edgetx-builder:2.12"
-    },
-    "v2.12.0-rc3": {
-      "build_container": "ghcr.io/edgetx/edgetx-builder:2.12"
-    },
-    "v2.12.0-rc2": {
-      "build_container": "ghcr.io/edgetx/edgetx-builder:2.12"
-    },
-    "v2.12.0-rc1": {
+    "v2.12.0": {
       "build_container": "ghcr.io/edgetx/edgetx-builder:2.12"
     },
     "v2.11.5": {
@@ -294,7 +285,7 @@
     },
     "t15pro": {
       "description": "Jumper T15 Pro",
-      "version_supported": ">= v2.12.0-rc1",
+      "version_supported": ">= v2.12.0",
       "tags": ["colorlcd", "bluetooth"]
     },
     "t16": {
@@ -368,7 +359,7 @@
     },
     "tx15": {
       "description": "RadioMaster TX15",
-      "version_supported": ">= v2.12.0-rc1",
+      "version_supported": ">= v2.12.0",
       "tags": ["colorlcd"]
     },
     "tx16s": {
@@ -377,7 +368,7 @@
     },
     "tx16smk3": {
       "description": "RadioMaster TX16S MK3",
-      "version_supported": ">= v2.12.0-rc3",
+      "version_supported": ">= v2.12.0",
       "tags": ["colorlcd", "bluetooth"]
     },
     "zorro": {