Make releasedata.Product usable in 'with' expression (#294)

This way the writing of the JSON file is handled automatically if the update does not fail.
It pave the way to further global improvements, such as a better error handling.

src/maven.py

@@ -7,24 +7,22 @@ METHOD = "maven"
 
 p_filter = sys.argv[1] if len(sys.argv) > 1 else None
 for product in endoflife.list_products(METHOD, p_filter):
-    product_data = releasedata.Product(product.name)
-    for config in product.get_auto_configs(METHOD):
-        start = 0
-        group_id, artifact_id = config.url.split("/")
+    with releasedata.ProductData(product.name) as product_data:
+        for config in product.get_auto_configs(METHOD):
+            start = 0
+            group_id, artifact_id = config.url.split("/")
 
-        while True:
-            url = f"https://search.maven.org/solrsearch/select?q=g:{group_id}+AND+a:{artifact_id}&core=gav&wt=json&start={start}&rows=100"
-            data = http.fetch_url(url).json()
+            while True:
+                url = f"https://search.maven.org/solrsearch/select?q=g:{group_id}+AND+a:{artifact_id}&core=gav&wt=json&start={start}&rows=100"
+                data = http.fetch_url(url).json()
 
-            for row in data["response"]["docs"]:
-                version_match = config.first_match(row["v"])
-                if version_match:
-                    version = config.render(version_match)
-                    date = datetime.fromtimestamp(row["timestamp"] / 1000, tz=timezone.utc)
-                    product_data.declare_version(version, date)
+                for row in data["response"]["docs"]:
+                    version_match = config.first_match(row["v"])
+                    if version_match:
+                        version = config.render(version_match)
+                        date = datetime.fromtimestamp(row["timestamp"] / 1000, tz=timezone.utc)
+                        product_data.declare_version(version, date)
 
-            start += 100
-            if data["response"]["numFound"] <= start:
-                break
-
-    product_data.write()
+                start += 100
+                if data["response"]["numFound"] <= start:
+                    break