update CI env vars

Author: dropwhile

.github/workflows/codeql-analysis.yml

@@ -10,6 +10,11 @@ on:
   schedule:
     - cron: '0 15 * * 4'
 
+# ensure testing on actual specified versions, and not auto-upgraded toolchain
+# versions
+env:
+  GOTOOLCHAIN: local
+
 jobs:
   analyse:
     name: Analyse

.github/workflows/unit-tests.yml

@@ -7,6 +7,12 @@ on:
     branches: [master]
   workflow_dispatch:
     branches: [master]
+
+# ensure testing on actual specified versions, and not auto-upgraded toolchain
+# versions
+env:
+  GOTOOLCHAIN: local
+
 jobs:
   build:
     name: Build