Only run benchmarking on pull requests

Author: MartinCarpentier

.github/workflows/continous-benchmark.yml

@@ -1,10 +1,11 @@
 name: Run benchmark
 on:
-  push:
+  pull_request:
+    branches: [ main ]
 
 jobs:
   benchmark:
-    name: Performance regression check
+    name: Continuous benchmarking
     runs-on: ubuntu-latest
 
     defaults:

src/GeoJSON.Text.Test.Benchmark/SerializeAndDeserialize.cs

@@ -46,7 +46,6 @@ public Text.Feature.FeatureCollection DeserializeFeatureCollection() => System.T
             ?? throw new NullReferenceException("Deserialization should not return a null value.");
 
         [Benchmark]
-        public string SerializeFeatureCollection() => System.Text.Json.JsonSerializer.Serialize(fileContents)
-            ?? throw new NullReferenceException("Deserialization should not return a null value.");
+        public string SerializeFeatureCollection() => System.Text.Json.JsonSerializer.Serialize(fileContents);
     }
 }