Relax generic package filename restrictions (#30135)

Now, the chars `=:;()[]{}~!@#$%^ &` are possible as well
Fixes #30134

---------

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>
(cherry picked from commit 1ad48f781eb0681561b083b49dfeff84ba51f2fe)

routers/api/packages/generic/generic_test.go

@@ -0,0 +1,65 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package generic
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestValidatePackageName(t *testing.T) {
+	bad := []string{
+		"",
+		".",
+		"..",
+		"-",
+		"a?b",
+		"a b",
+		"a/b",
+	}
+	for _, name := range bad {
+		assert.False(t, isValidPackageName(name), "bad=%q", name)
+	}
+
+	good := []string{
+		"a",
+		"1",
+		"a-",
+		"a_b",
+		"c.d+",
+	}
+	for _, name := range good {
+		assert.True(t, isValidPackageName(name), "good=%q", name)
+	}
+}
+
+func TestValidateFileName(t *testing.T) {
+	bad := []string{
+		"",
+		".",
+		"..",
+		"a?b",
+		"a/b",
+		" a",
+		"a ",
+	}
+	for _, name := range bad {
+		assert.False(t, isValidFileName(name), "bad=%q", name)
+	}
+
+	good := []string{
+		"-",
+		"a",
+		"1",
+		"a-",
+		"a_b",
+		"a b",
+		"c.d+",
+		`-_+=:;.()[]{}~!@#$%^& aA1`,
+	}
+	for _, name := range good {
+		assert.True(t, isValidFileName(name), "good=%q", name)
+	}
+}