fix(runCognium): strip Maven download noise from benchmark_version

getBenchmarkVersion.sh runs mvn and pipes through grep -v '[INFO]', but
Maven's transfer progress lines ("Downloading from central: ...",
"Downloaded from central: ...") have no [INFO] prefix so they bypass
the filter. On a cold Maven cache these lines get captured into
benchmark_version, producing an invalid filename like:

  results/Benchmark_Downloading from central: https://...1.2-cognium-v1.6.9.sarif

The fix adds 2>/dev/null to silence stderr and pipes through
grep -E '^[0-9]+\.[0-9]' to accept only lines that start with digits —
the actual version string (e.g. 1.2). All Maven noise is discarded.

The second run worked because the local Maven cache was warm so no
download lines were emitted.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Asok Shanmugam

scripts/runCognium.sh

@@ -7,7 +7,7 @@ source scripts/requireCommand.sh
 
 requireCommand cognium
 
-benchmark_version=$(scripts/getBenchmarkVersion.sh)
+benchmark_version=$(scripts/getBenchmarkVersion.sh 2>/dev/null | grep -E '^[0-9]+\.[0-9]')
 cognium_version=$(cognium --version | grep -oE '[0-9]+\.[0-9]+\.[0-9]+')
 result_file="results/Benchmark_$benchmark_version-cognium-v$cognium_version.sarif"