ci: Remove expectation on libbpf_strict feature

In upstream commit 9b8107553424 ("bpftool: remove support of --legacy
option for bpftool"), the "libbpf_strict" feature display has been
removed from bpftool. The reasoning is that now that bpftool relies on
libbpf >= 1.0, bpftool is de facto always in strict mode, so there's no
need to display the feature state.

This commit updates the relevant feature checks in the CI workflow.

Signed-off-by: Quentin Monnet <[email protected]>

Author: qmonnet

.github/workflows/build.yaml

@@ -14,7 +14,7 @@ jobs:
         os: [ubuntu-18.04, ubuntu-20.04, ubuntu-22.04]
     runs-on: ${{ matrix.os }}
     env:
-      FEATURES: .llvm and .libbpf_strict
+      FEATURES: .llvm
 
     steps:
       - name: Checkout repository