Drop lock files from repo (#1282)

web/particle_background/pubspec.lock

@@ -1,64 +0,0 @@
-# Generated by pub
-# See https://dart.dev/tools/pub/glossary#lockfile
-packages:
-  characters:
-    dependency: transitive
-    description:
-      name: characters
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.2.0"
-  collection:
-    dependency: transitive
-    description:
-      name: collection
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.16.0"
-  flutter:
-    dependency: "direct main"
-    description: flutter
-    source: sdk
-    version: "0.0.0"
-  flutter_lints:
-    dependency: "direct main"
-    description:
-      name: flutter_lints
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.0.1"
-  lints:
-    dependency: transitive
-    description:
-      name: lints
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.0.0"
-  material_color_utilities:
-    dependency: transitive
-    description:
-      name: material_color_utilities
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.1.4"
-  meta:
-    dependency: transitive
-    description:
-      name: meta
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "1.7.0"
-  sky_engine:
-    dependency: transitive
-    description: flutter
-    source: sdk
-    version: "0.0.99"
-  vector_math:
-    dependency: transitive
-    description:
-      name: vector_math
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "2.1.2"
-sdks:
-  dart: ">=2.17.0-206.0.dev <3.0.0"