feat(awesome-assertions): Added new project WireMock.Net.AwesomeAssertions (#1273)

* feat(awesome-assertions): Added new project WireMock.Net.AwesomeAssertions

* feat(awesome-assertions): Applied dotnet naming convention for private readonly fields

---------

Co-authored-by: Francesco Venturoli <f.venturoli@crif.com>

src/WireMock.Net.AwesomeAssertions/Assertions/WireMockAssertions.WithProxy.cs

@@ -0,0 +1,36 @@
+// Copyright © WireMock.Net
+
+#pragma warning disable CS1591
+using System;
+
+// ReSharper disable once CheckNamespace
+namespace WireMock.FluentAssertions;
+
+public partial class WireMockAssertions
+{
+    [CustomAssertion]
+    public AndWhichConstraint<WireMockAssertions, string> WithProxyUrl(string proxyUrl, string because = "", params object[] becauseArgs)
+    {
+        var (filter, condition) = BuildFilterAndCondition(request => string.Equals(request.ProxyUrl, proxyUrl, StringComparison.OrdinalIgnoreCase));
+
+        _chain
+            .BecauseOf(because, becauseArgs)
+            .Given(() => RequestMessages)
+            .ForCondition(requests => CallsCount == 0 || requests.Any())
+            .FailWith(
+                "Expected {context:wiremockserver} to have been called with proxy url {0}{reason}, but no calls were made.",
+                proxyUrl
+            )
+            .Then
+            .ForCondition(condition)
+            .FailWith(
+                "Expected {context:wiremockserver} to have been called with proxy url {0}{reason}, but didn't find it among the calls with {1}.",
+                _ => proxyUrl,
+                requests => requests.Select(request => request.ProxyUrl)
+            );
+
+        FilterRequestMessages(filter);
+
+        return new AndWhichConstraint<WireMockAssertions, string>(this, proxyUrl);
+    }
+}