scouting: Fix naming of assemble_static_files rule

Originally, we only had pictures in that rule so naming the attribute
`pictures` made sense. But now we have a bunch of other kinds of files
in there. Let's rename it to `srcs` to be more consistent with other
rules.

Change-Id: Ie53f6cd040db311241807c3acee0ac6d4dbd0875
Signed-off-by: Philipp Schrader <philipp.schrader@gmail.com>
diff --git a/scouting/www/BUILD b/scouting/www/BUILD
index 46742e3..685fe14 100644
--- a/scouting/www/BUILD
+++ b/scouting/www/BUILD
@@ -42,12 +42,12 @@
 
 assemble_static_files(
     name = "static_files",
-    app_files = ":app",
-    pictures = [
-        "//third_party/y2024/field:pictures",
-        ":ngsw-worker.js",
+    srcs = [
         ":ngsw.json",
+        ":ngsw-worker.js",
+        "//third_party/y2024/field:pictures",
     ],
+    app_files = ":app",
     replace_prefixes = {
         "prod": "",
         "dev": "",