[flutter_tools] migrate to null safe mustache (#77400)

dev/tools/pubspec.yaml

@@ -50,7 +50,7 @@ dependencies:
   matcher: 0.12.10 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   mime: 1.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   multicast_dns: 0.2.2 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
-  mustache_template: 1.0.0+1 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+  mustache_template: 2.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   native_stack_traces: 0.3.7 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   package_config: 1.9.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   pedantic: 1.11.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
@@ -94,4 +94,4 @@ dev_dependencies:
   js: 0.6.3 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   node_preamble: 1.4.13 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
 
-# PUBSPEC CHECKSUM: b55a
+# PUBSPEC CHECKSUM: fbfe

packages/flutter_tools/pubspec.yaml

@@ -22,7 +22,7 @@ dependencies:
   intl: 0.17.0
   meta: 1.3.0
   multicast_dns: 0.2.2
-  mustache_template: 1.0.0+1
+  mustache_template: 2.0.0
   package_config: 1.9.3
   process: 4.1.0
   fake_async: 1.2.0
@@ -108,4 +108,4 @@ dartdoc:
   # Exclude this package from the hosted API docs.
   nodoc: true
 
-# PUBSPEC CHECKSUM: 7938
+# PUBSPEC CHECKSUM: 09dc