[FIX] base, snailmail: Swaziland is now Eswatini

Swaziland was renamed to Eswatini in 2018. Time to update naming in Odoo.
We choose to make it in 16 as

  * it is the newest stable, not much people are using it in production, aka
    most people will have the updated name;
  * there is no need to rename it for all production databases previously
    as if used, it is easy to update its naming from Odoo directly;

Cheers !

X-original-commit: 4f97baa5b4d01b4510f0adc7064ec2846612a481
Part-of: odoo/odoo#104770

addons/snailmail/country_utils.py

@@ -215,7 +215,7 @@ SNAILMAIL_COUNTRIES = {
     "SV": "El Salvardor",
     "SX": "Sint Maarten",
     "SY": "Syria",
-    "SZ": "Swaziland",
+    "SZ": "Eswatini",
     "TA": "Tristan da Cunha",
     "TC": "Turks and Caicos",
     "TD": "Chad",

odoo/addons/base/data/res_country_data.xml

@@ -1348,7 +1348,7 @@
             <field eval="963" name="phone_code" />
         </record>
         <record id="sz" model="res.country">
-            <field name="name">Swaziland</field>
+            <field name="name">Eswatini</field>
             <field name="code">sz</field>
             <field name="currency_id" ref="SZL" />
             <field eval="268" name="phone_code" />