ci: Updates to push/PR paths for builds

- Remove schemas because there doesn't seem to be any jobs that operate
  on these files. I don't remember the reason that it was added in the
  first place; but can deal with that later if I notice something wrong.
- Add props/targets files so that we rebuild when we update package
  versions, etc.

.github/workflows/build.yml

@@ -9,9 +9,10 @@ on:
       - ".github/workflows/reusable-build.yml"
       - "src/**"
       - "tests/**"
-      - "schemas/**"
       - "docker/**"
       - "ci/**"
+      - "**.props"
+      - "**.targets"
 
   pull_request:
     paths:
@@ -20,9 +21,10 @@ on:
       - ".github/workflows/reusable-build.yml"
       - "src/**"
       - "tests/**"
-      - "schemas/**"
       - "docker/**"
       - "ci/**"
+      - "**.props"
+      - "**.targets"
 
 jobs:
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