Bump CPU threshold limit to 55 (#125)

* Issue #122 showed that the CPU Usage can be as high as 55 percent at startup
* Since the CPU usage is going down, we don't suspect it is a memory leak
* We want to alarm on continuous HIGH CPU Usage, so we just push the limit up for now

Author: NathanielRN

.github/workflows/soak-testing.yml

@@ -22,7 +22,7 @@ env:
   AWS_DEFAULT_REGION: us-east-1
   DEFAULT_TEST_DURATION_MINUTES: 300
   HOSTMETRICS_INTERVAL_SECS: 600
-  CPU_LOAD_THRESHOLD: 45
+  CPU_LOAD_THRESHOLD: 55
   TOTAL_MEMORY_THRESHOLD: 4294967296 # 4 GiB
   MAX_BENCHMARKS_TO_KEEP: 100
   # TODO: We might be able to adapt the "Soak Tests" to be "Overhead Tests".