v0.3.0

UnsafeAtomics v0.3.0

Diff since v0.2.1

Merged pull requests:

• Use atomic_pointer* methods when available (#14) (@jpsamaroo)
• Use a package extension for UnsafeAtomicsLLVM (#15) (@vchuravy)
• Fix load and store for sizeof(T) == 0 (#18) (@vchuravy)
• Implement UnsafeAtomics.fence (#19) (@vchuravy)
• implement syncscopes everywhere (#20) (@vchuravy)
• Dispatch to LLVM atomic OP (#21) (@pxl-th)

Closed issues:

• Properly support fence (#16)
• Support for passing synchronization scopes (#17)