Say when a newer release is out, and stop there

A check on the releases page once a day: at start, on a timer while Dikte
runs, from the General tab on demand, and from `dikte update` at a terminal.
What it finds goes in the tray menu and in one notification per version, and
opens the release page.

Nothing is downloaded and nothing is installed. The four downloads are
installed four different ways and three of those belong to the platform: a
Mac bundle cannot rewrite itself while it is running, the Windows setup has
an uninstall entry of its own, an AppImage is a file kept wherever its owner
keeps it, and a checkout is updated with git. Being wrong about any one of
them means an installation somebody has to repair by hand.

Versions are compared by their numbers alone. A build off master carries the
released number with its commit after it, and that build is ahead of the
release it names rather than behind it; read as a version suffix, every
nightly would be told to go back to a release it had already passed.

The clock lives in its own file rather than in the settings, since a check
runs while the settings window may be open and a background write into
config.json is what would overwrite whatever it holds.

dikte/i18n.py

@@ -192,6 +192,25 @@ TR = {
     "Silence threshold": "Sessizlik eşiği",
     "Keep audio files ({path})": "Ses kayıtlarını sakla ({path})",
 
+    # --- updates --------------------------------------------------------
+    "Updates": "Güncelleme",
+    "Look for a newer version once a day": "Günde bir kez yeni sürüm var mı diye bak",
+    "Dikte only looks. What it finds opens the release page in your browser; "
+    "it downloads and installs nothing by itself.":
+        "Dikte yalnızca bakar. Bulduğu şey tarayıcında sürüm sayfasını açar; "
+        "kendi başına hiçbir şey indirmez ve kurmaz.",
+    "Check now": "Şimdi bak",
+    "Looking…": "Bakılıyor…",
+    "Open the release page": "Sürüm sayfasını aç",
+    "This is Dikte {version}.": "Buradaki sürüm Dikte {version}.",
+    "Dikte {version} is the newest release.": "En yeni sürüm zaten bu: Dikte {version}.",
+    "Dikte {version} is out; this is {current}.":
+        "Dikte {version} çıkmış; buradaki sürüm {current}.",
+    "Dikte {version} is out…": "Dikte {version} çıkmış…",
+    "Dikte {version} is out. The tray menu has the release page.":
+        "Dikte {version} çıkmış. Sürüm sayfası tepsi menüsünde.",
+    "{repo} has published no release.": "{repo} için yayımlanmış sürüm yok.",
+
     # --- settings: api --------------------------------------------------
     "Keys": "Anahtarlar",
     "Speech to text": "Sesi yazıya çevirme",