feat: update sql solution to lc problem: No.2339 (#1822)

Author: thinkasany

solution/2300-2399/2339.All the Matches of the League/README.md

@@ -67,7 +67,7 @@ Teams 表:
 SELECT t1.team_name AS home_team, t2.team_name AS away_team
 FROM
     Teams AS t1
-    CROSS JOIN Teams AS t2
+    JOIN Teams AS t2
 WHERE t1.team_name != t2.team_name;
 ```
 

solution/2300-2399/2339.All the Matches of the League/README_EN.md

@@ -62,7 +62,7 @@ Teams table:
 SELECT t1.team_name AS home_team, t2.team_name AS away_team
 FROM
     Teams AS t1
-    CROSS JOIN Teams AS t2
+    JOIN Teams AS t2
 WHERE t1.team_name != t2.team_name;
 ```
 

solution/2300-2399/2339.All the Matches of the League/Solution.sql

@@ -2,5 +2,5 @@
 SELECT t1.team_name AS home_team, t2.team_name AS away_team
 FROM
     Teams AS t1
-    CROSS JOIN Teams AS t2
+    JOIN Teams AS t2
 WHERE t1.team_name != t2.team_name;