Update datagen to TZDB 2025c (#7306)

Some timestamps in `America/Tijuana` in the 70s change, but only wrt to
DST, so no CLDR or metazones changes are needed, so there's no data diff
for ICU4X.

Author: robertbastian

provider/source/src/lib.rs

@@ -119,7 +119,7 @@ impl SourceDataProvider {
     pub const TESTED_SEGMENTER_LSTM_TAG: &'static str = "v0.1.0";
 
     /// The TZDB tag that has been verified to work with this version of `SourceDataProvider`.
-    pub const TESTED_TZDB_TAG: &'static str = "2025b";
+    pub const TESTED_TZDB_TAG: &'static str = "2025c";
 
     /// A provider using the data that has been verified to work with this version of `SourceDataProvider`.
     ///