Issue #4: Added From trait (#7)

* #4 Added `From` trait

This adds the `from()` and `tryFrom()` methods to pure enums, and the `fromName()` and `tryFromName()` methods for all enum types.

* Code review changes

Dropped support for fragile indexes on pure enums

* Dropped unnecessary array_pop()

* import ValueError

* remove import

Co-authored-by: Samuel Štancl <samuel@archte.ch>
Co-authored-by: Samuel Štancl <samuel.stancl@gmail.com>

src/From.php

@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ArchTech\Enums;
+
+use ValueError;
+
+trait From
+{
+    /**
+     * Gets the Enum by name, if it exists, for "Pure" enums.
+     *
+     * This will not override the `from()` method on BackedEnums
+     *
+     * @throws ValueError
+     */
+    public static function from(string $case): static
+    {
+        return static::fromName($case);
+    }
+
+    /**
+     * Gets the Enum by name, if it exists, for "Pure" enums.
+     *
+     * This will not override the `tryFrom()` method on BackedEnums
+     */
+    public static function tryFrom(string $case): ?static
+    {
+        return static::tryFromName($case);
+    }
+
+    /**
+     * Gets the Enum by name.
+     *
+     * @throws ValueError
+     */
+    public static function fromName(string $case): static
+    {
+        return static::tryFromName($case) ?? throw new ValueError('"' . $case . '" is not a valid name for enum "' . static::class . '"');
+    }
+
+    /**
+     * Gets the Enum by name, if it exists.
+     */
+    public static function tryFromName(string $case): ?static
+    {
+        $cases = array_filter(
+            static::cases(),
+            fn ($c) => $c->name === $case
+        );
+
+        return array_values($cases)[0] ?? null;
+    }
+}