PaddleMaterials v0.3.0

What's Changed

• refactor & standardize ppmat and fix last errors for diffnmr & infgcn by @leeleolay in #310
• [codex] add PaddleMaterials project homepage by @leeleolay in #311
• [codex] add homepage badge and single-line inference command by @leeleolay in #312
• docs: refine homepage Chinese terminology by @leeleolay in #313
• refactor predictor/sampler by @leeleolay in #314

Full Changelog: v0.2.1...v0.3.0