Fix bad character escape in Caen to Evreux.

The escape sequence looks to be valid according to the spec (although it
would need to be double quoted, but that doesn't fix it), but Python's
parser doesn't appear to handle that. Just use ü.

https://github.com/dcs-liberation/dcs_liberation/issues/2786

resources/campaigns/caen_to_evreux.yaml

@@ -2,7 +2,11 @@
 name: Normandy - From Caen to Evreux
 theater: Normandy
 authors: Khopa
-description: <p>This is a light scenario on the Normandy map.</p><p>August 1944, allied forces are pushing from Caen/Carpiquet to the cities of Lisieux and Evreux.<p>Lisieux is an important logistic hub for the Werhmacht, and Evreux airbase is hosting most of the Luftwaffe forces in the region.</p>
+description:
+  <p>This is a light scenario on the Normandy map.</p><p>August 1944, allied
+  forces are pushing from Caen/Carpiquet to the cities of Lisieux and
+  Evreux.<p>Lisieux is an important logistic hub for the Werhmacht, and Evreux
+  airbase is hosting most of the Luftwaffe forces in the region.</p>
 recommended_player_faction: Allies 1944
 recommended_enemy_faction: Germany 1944
 recommended_start_date: 1944-07-04
@@ -14,7 +18,7 @@ squadrons:
   26:
     - primary: BARCAP
       aircraft:
-        - Bf 109 K-4 Kurf\u00fcrst
+        - Bf 109 K-4 Kurfürst
     - primary: BARCAP
       aircraft:
         - Fw 190 A-8 Anton
@@ -32,7 +36,7 @@ squadrons:
   40:
     - primary: BARCAP
       aircraft:
-        - Bf 109 K-4 Kurf\u00fcrst
+        - Bf 109 K-4 Kurfürst
     - primary: BARCAP
       aircraft:
         - Fw 190 A-8 Anton
@@ -67,7 +71,7 @@ squadrons:
       secondary: any
     - primary: DEAD
       secondary: any
-  # Ford_AF 
+  # Ford_AF
   31:
     - primary: BARCAP
       aircraft:
@@ -93,4 +97,4 @@ squadrons:
         - B-17G Flying Fortress
     - primary: AEW&C
     - primary: Refueling
-    - primary: Transport
+    - primary: Transport