Add MB config for Fuchsia FYI bot

tools/mb/mb_config.pyl

Index: tools/mb/mb_config.pyl
diff --git a/tools/mb/mb_config.pyl b/tools/mb/mb_config.pyl
index eaf175f6f90ca242f4354974e771b5adf6131232..3c279034fdd8094182395515202d2790580fb201 100644
--- a/tools/mb/mb_config.pyl
+++ b/tools/mb/mb_config.pyl
@@ -177,6 +177,7 @@
       'CrWinClngLLD64dbg': 'clang_tot_full_symbols_shared_debug_use_lld',
       'CrWinClngLLDdbg': 'clang_tot_full_symbols_shared_debug_use_lld_x86',
       'EarlGreyiOS': 'ios',
+      'Fuchsia': 'release_bot_fuchsia',
       'GomaCanaryiOS': 'ios',
       'ios-simulator': 'ios',
       'Headless Linux (dbg)': 'headless_linux_debug_bot',
@@ -1367,6 +1368,10 @@
       'release_bot', 'ozone', 'ozone_linux',
     ],
 
+    'release_bot_fuchsia': [
+      'release_bot', 'fuchsia',
+    ],
+
     'ozone_linux_release_trybot': [
       'release_trybot', 'ozone', 'ozone_linux',
     ],
@@ -1807,6 +1812,10 @@
                   'use_xkbcommon=true'),
     },
 
+    'fuchsia': {
+      'gn_args': 'target_os="fuchsia"',
+    },
+
     'pdf_xfa': {
       'gn_args': 'pdf_enable_xfa=true',
     },