Update build.yml for Azure Pipelines

Author: StefanoLusardi

ci/build.yml

@@ -104,14 +104,14 @@ jobs:
 
         - task: Cache@2
           inputs:
-            key: 'venv $(Agent.JobName) | scripts/requirements.txt'
+            key: '"venv_$(Agent.JobName)" | scripts/requirements.txt'
             path: '$(Build.SourcesDirectory)/.venv'
             cacheHitVar: 'VENV_CACHE_RESTORED'
           displayName: 'Cache Virtual Environment'
 
         - task: Cache@2
           inputs:
-            key: 'conan $(Agent.JobName) | sdk/examples/conanfile.txt | sdk/tests/conanfile.txt'
+            key: '"conan_$(Agent.JobName)" | sdk/examples/conanfile.txt | sdk/tests/conanfile.txt'
             path: '$(Build.SourcesDirectory)/.conan'
           displayName: 'Cache Conan'