With the backport of TDigest, the build started failing compiling with Java 20 with the following error:

```
> Task :libs:elasticsearch-tdigest:compileJava FAILED
../elasticsearch/libs/tdigest/src/main/java/org/elasticsearch/tdigest/SortingDigest.java:57: warning: [lossy-conversions] implicit cast from long to int in compound assignment is possibly lossy
            valuesToAddCount += other.size();
                                          ^
error: warnings found and -Werror specified
1 error
1 warning

```
Java 20 is more picky about lossy conversions,

libs/tdigest/src/main/java/org/elasticsearch/tdigest/SortingDigest.java
compress();
        return Dist.cdf(x, values);
    }
    @Override
    public double quantile(double q) {
        compress();
        return Dist.quantile(q, values);
    }
    @Override
    public Collection<Centroid> centroids() {
        compress();
        return new AbstractCollection<>() {
            @Override
            public Iterator<Centroid> iterator() {
                return new Iterator<>() {
                    int i = 0;
                    @Override
                    public boolean hasNext() {
                        return i < values.size();
                    }
                    @Override
                    public Centroid next() {
                        Centroid rc = new Centroid(values.get(i), 1);
                        i++;
                        return rc;
                    }
                    @Override
                    public void remove() {
                        throw new UnsupportedOperationException("Default operation");
                    }