feat: add QIcon backed by iconify (#209)

* feat: add iconify

* update docs

* update docs

* rearrange

* update example

* update test deps

* importorskip

* Update src/superqt/iconify/__init__.py

Co-authored-by: Grzegorz Bokota <bokota+github@gmail.com>

* Update src/superqt/iconify/__init__.py

Co-authored-by: Grzegorz Bokota <bokota+github@gmail.com>

* merge

* change test

* bump dep

* change doc

* Update src/superqt/iconify/__init__.py

Co-authored-by: Grzegorz Bokota <bokota+github@gmail.com>

* pragma and bump version

---------

Co-authored-by: Grzegorz Bokota <bokota+github@gmail.com>

tests/test_iconify.py

@@ -0,0 +1,22 @@
+from typing import TYPE_CHECKING
+
+import pytest
+from qtpy.QtWidgets import QPushButton
+
+from superqt import QIconifyIcon
+
+if TYPE_CHECKING:
+    from pytestqt.qtbot import QtBot
+
+
+def test_qiconify(qtbot: "QtBot", monkeypatch: "pytest.MonkeyPatch") -> None:
+    monkeypatch.setenv("PYCONIFY_CACHE", "0")
+    pytest.importorskip("pyconify")
+
+    icon = QIconifyIcon("bi:alarm-fill", color="red", rotate=90)
+    assert icon.path.name.endswith(".svg")
+
+    btn = QPushButton()
+    qtbot.addWidget(btn)
+    btn.setIcon(icon)
+    btn.show()