Lower target-throughput for geonames term and phrase queries (elastic…

…#134)

From observation in the nightly environment we can see that occasionally
the phrase and term query may take >300ms and >1000ms. This leads to
unnecessary spikes in the latency charts.

Relates to elastic/elasticsearch#61957

geonames/challenges/default.json

@@ -77,13 +77,13 @@
           "operation": "term",
           "warmup-iterations": 500,
           "iterations": 1000,
-          "target-throughput": 150
+          "target-throughput": 140
         },
         {
           "operation": "phrase",
           "warmup-iterations": 500,
           "iterations": 1000,
-          "target-throughput": 150
+          "target-throughput": 140
         },
         {
           "operation": "country_agg_uncached",