Revert "Revert "CI: remove manylinux1 target" because manylinux2010 problematic for some pylsl users."

manylinux1 doesn't build on Azure anymore, I guess that's why the original commit was there in the first place.

This reverts commit c5020c8.

Author: cboulay

azure-pipelines.yml

@@ -15,11 +15,4 @@ stages:
     - bash: strip --strip-unneeded liblsl.so
     - publish: liblsl.so
       artifact: manylinux2010
-  - job: manylinux1
-    pool: { vmImage: 'ubuntu-latest' }
-    container: quay.io/pypa/manylinux1_x86_64:latest
-    steps:
-    - bash: CFLAGS="-flto -static-libstdc++ -std=c++11" ./standalone_compilation_linux.sh
-    - bash: strip --strip-unneeded liblsl.so
-    - publish: liblsl.so
-      artifact: manylinux1
+