Firrtl v1.4.2

Highlights

• Improve performance of LowerTypes renaming (bp #2024) (#2025)
• Suport ir.SubAccess in Utils.splitRef (#2021) (#2070)
• Add --dont-fold option to disable folding prim ops (#2040) (#2050)

Bug fixes

• Add newline in the end of LoFIRRTL file (#2015) (#2016)
• fix scaladoc for ReferenceTarget (#2014) (#2020)
• Cleanup some warnings (#2032) (#2051)
• Stop padding multiply and divide ops (#2058) (#2061)

Miscellaneous

• Deprecate ToWorkingIR (#2028) (#2067)
• ConstantPropagation: make RemoveValidIf an optional dependency (#2027) (#2066)
• smt: run DeadCodeElimination after PropagatePresetAnnotations (#2036) (#2043)

Infrastructure

• Fix Mergify badge in README (#1974) (#2010)
• Fix post-merge publishing (#2055) (#2056)
• Bump to Scala 2.12.13 and 2.13.4 (bp #2053) (#2054)
• Restore scalafmt CI check (#2047) (#2049)
• Switch from Travis to Github Actions CI (#2041) (#2044)