automatically bump pkgrel on version duplicates

The new --(no-)increment flag has been added to add, update and rebuild
subcommands. In case if it is true and package version is the same as in
repository, it will automatically bump pkgrel appending (increasing)
minor part of it (e.g. 1.0.0-1 -> 1.0.0-1.1).

Inn order to implement this, the shadow (e.g. it will not store it in
database) patch for pkgrel will be created

tests/ahriman/models/test_package.py

@@ -501,6 +501,30 @@ def test_is_outdated_fresh_package(package_ahriman: Package, repository_paths: R
     actual_version_mock.assert_not_called()
 
 
+def test_next_pkgrel(package_ahriman: Package) -> None:
+    """
+    must correctly bump pkgrel
+    """
+    assert package_ahriman.next_pkgrel(package_ahriman.version) == "1.1"
+
+    package_ahriman.version = "1.0.0-1.1"
+    assert package_ahriman.next_pkgrel(package_ahriman.version) == "1.2"
+
+    package_ahriman.version = "1.0.0-1.2.1"
+    assert package_ahriman.next_pkgrel(package_ahriman.version) == "1.2.2"
+
+    package_ahriman.version = "1:1.0.0-1"
+    assert package_ahriman.next_pkgrel("1:1.0.1-1") is None
+    assert package_ahriman.next_pkgrel("2:1.0.0-1") is None
+
+    package_ahriman.version = "1.0.0-1.1"
+    assert package_ahriman.next_pkgrel("1.0.1-2") is None
+    assert package_ahriman.next_pkgrel("1.0.0-2") == "2.1"
+
+    package_ahriman.version = "1.0.0-2"
+    assert package_ahriman.next_pkgrel("1.0.0-1.1") is None
+
+
 def test_build_status_pretty_print(package_ahriman: Package) -> None:
     """
     must return string in pretty print function