Complete release notes for v0.0.5

Issue references are not being shown in release notes. Also, these are the remaining changes to add

fix ambiguity in Graphs, with dedicated constructors for each op #275
delete hashWithSalt for Array #254
explicitly register parameters #250
add graph metadata to tensors #247
improve type-safety around FFI #274
build XLA graph from AST Expr (formerly Graph), providing a central symbolic graph representation #294
resolve graph hash collisions #289
refactor cached to be more readable #256
cache XlaOp pointers for each XlaBuilder #244

joelberkeley / spidr