tools: copy hdr_histogram_internal.h in update-histogram.sh

HdrHistogram_c 0.12.0 added a private header,
src/hdr_histogram_internal.h, which src/hdr_tests.h now includes.
update-histogram.sh copies a fixed list of files, so the automated
update to 0.12.0 would leave deps/histogram without it and fail to
compile. Add the header to the list.

Signed-off-by: fcostaoliveira <filipe@redis.com>
PR-URL: #66528
Reviewed-By: Richard Lau <richard.lau@ibm.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>

Author: fcostaoliveira

tools/dep_updaters/update-histogram.sh

@@ -54,7 +54,7 @@ mv "HdrHistogram_c-$NEW_VERSION" histogram
 
 cp "$WORKSPACE/histogram/include/hdr/hdr_histogram_version.h" "$WORKSPACE/histogram/include/hdr/hdr_histogram.h" "$DEPS_DIR/histogram/include/hdr"
 
-cp "$WORKSPACE/histogram/src/hdr_atomic.h" "$WORKSPACE/histogram/src/hdr_malloc.h" "$WORKSPACE/histogram/src/hdr_tests.h" "$WORKSPACE/histogram/src/hdr_histogram.c" "$DEPS_DIR/histogram/src"
+cp "$WORKSPACE/histogram/src/hdr_atomic.h" "$WORKSPACE/histogram/src/hdr_malloc.h" "$WORKSPACE/histogram/src/hdr_tests.h" "$WORKSPACE/histogram/src/hdr_histogram_internal.h" "$WORKSPACE/histogram/src/hdr_histogram.c" "$DEPS_DIR/histogram/src"
 
 # Update the version number on maintaining-dependencies.md
 # and print the new version as the last line of the script as we need