rename to Containerfile; then we don't need -f and CI can build

Author: nickdesaulniers

llvm-project/Dockerfile.bootstrap renamed to llvm-project/Containerfile

@@ -1,4 +1,4 @@
 #!/usr/bin/env sh
 wget --no-clobber https://github.com/llvm/llvm-project/releases/download/llvmorg-14.0.1/llvm-project-14.0.1.src.tar.xz
-docker build --tag clangbuiltlinux/llvm-project:latest . -f Dockerfile.bootstrap
+docker build --tag clangbuiltlinux/llvm-project:latest .
 docker cp llvm-project:/usr/local/bin/clang-14 clang