Update build scripts

Author: rdeago

build.cake

@@ -15,6 +15,7 @@
 #load "./build/process.cake"
 #load "./build/public-api.cake"
 #load "./build/setup-teardown.cake"
+#load "./build/utilities.cake"
 #load "./build/versioning.cake"
 #load "./build/workspace.cake"
 

build/git.cake

@@ -129,11 +129,10 @@ static (SemanticVersion? Latest, SemanticVersion? LatestStable) GitGetLatestVers
                          .Where(static x => x.StartsWith("tag: "))
                          .Select(static x => x.Substring(5))
                          .Select(static x => {
-                            SemanticVersion? version = null;
-                            var result = SemanticVersion.TryParse(x, out version);
+                            _ = SemanticVersion.TryParse(x, out var version);
                             return version;
                          })
-                         .Where(static x => x != null);
+                         .WhereNotNull();
 
     SemanticVersion? latest = null;
     SemanticVersion? latestStable = null;

build/utilities.cake

@@ -0,0 +1,41 @@
+// Copyright (C) Tenacom and contributors. Licensed under the MIT license.
+// See LICENSE file in the project root for full license information.
+
+#nullable enable
+
+// ---------------------------------------------------------------------------------------------
+// Miscellaneous utilities
+// ---------------------------------------------------------------------------------------------
+
+using System;
+using System.Linq;
+
+/*
+ * Summary     : Filters a sequence of nullable values, taking only those that are not null.
+ * Type params : T - The type of the elements of this.
+ * Params      : this - An IEnumerable<T> to filter.</param>
+ * Returns     : An IEnumerable<T> that contains elements from the input sequence that are not null.
+ */
+static IEnumerable<T> WhereNotNull<T>(this IEnumerable<T?> @this)
+    where T : class
+{
+    return @this.Where(IsNotNull) as IEnumerable<T>;
+
+    static bool IsNotNull(T? x) => x is not null;
+}
+
+/*
+ * Summary     : Filters a sequence of nullable values, taking only those that are not null.
+ * Type params : T - The type of the elements of this.
+ * Params      : this - An IEnumerable<T> to filter.</param>
+ * Returns     : An IEnumerable<T> that contains elements from the input sequence that are not null.
+ */
+public static IEnumerable<T> WhereNotNull<T>(this IEnumerable<T?> @this)
+    where T : struct
+{
+    return @this.Where(IsNotNull).Select(GetValue);
+
+    static bool IsNotNull(T? x) => x.HasValue;
+
+    static T GetValue(T? x) => x!.Value;
+}