Add clang19 to Travis CI configuration

Author: Ekaterina Sokolova

travis/Dockerfile.in

@@ -7,7 +7,7 @@ RUN apk add --no-cache \
 	perl perl-ipc-run perl-dev perl-app-cpanminus perl-dbi \
 	make musl-dev gcc bison flex coreutils \
 	zlib-dev libedit-dev \
-	pkgconf icu-dev clang clang15 clang-analyzer;
+	pkgconf icu-dev clang clang15 clang19 clang-analyzer;
 
 # Environment
 ENV LANG=C.UTF-8 PGDATA=/pg/data