Bump to 1.8 (#291)

[Diff since v1.7.0](v1.7.0...v1.7.1)

**Merged pull requests:**
- Support MKL_jll 2023 (#270) (@dlfivefifty)

[Diff since v1.6.0](v1.6.0...v1.7.0)

**Closed issues:**
- Normalization of FFTW.r2r for FFTW.RODFT00 (#268)

**Merged pull requests:**
- fix typos (#265) (@spaette)
- remove tuple specialization of fix_kinds (#266) (@jishnub)
- reduce allocations in dims_howmany (#269) (@jishnub)

[Diff since v1.5.0](v1.5.0...v1.6.0)

**Closed issues:**
- FFTW could not create plan for `fft(n × m × 1 array, 2)` (#142)
- why mkl can not get fft(x,1)? (#237)
- I didn't ask for plan_bfft, but got MethodError: no method matching plan_bfft(::Vector{Number}, ::UnitRange{Int64}) (#244)
- FFTW.fft() fails to calculate spectrum (#250)
- MKL: FFTW could not create plan (#252)

**Merged pull requests:**
- Create Invalidations.yml (#251) (@ranocha)
- Improve type inference in `plan_r2r` (#253) (@jishnub)
- inference + allocation in `fix_kinds` (#254) (@jishnub)
- remove test_broken on master (#257) (@jishnub)
- improve type inference in DCTPlan (#259) (@jishnub)
- Update GitHub Actions setup and move to Cirrus for other platforms (#262) (@giordano)
- Bump version to v1.5.1 (#263) (@jishnub)
- bump to 1.6 since new type params were added (#264) (@stevengj)

[Diff since v1.4.6](v1.4.6...v1.5.0)

**Closed issues:**
- `get` version of `FFTW.set_num_threads()`? (#117)
- Please tag a new version (with support for MKL 2022) (#230)

**Merged pull requests:**
- Add get_num_threads (#171) (@galenlynch)

[Diff since v1.4.5](v1.4.5...v1.4.6)

**Closed issues:**
- Migrate to travis-ci.com (#166)
- Darwin ARM: libfftw3 not defined (#187)
- Unable to install latest version of FFTW on Julia 1.6 (#206)
- Problem with `FFTW=1.4.3` ignoring `DEPOT_PATH` variable at runtime (#208)
- Latest FFTW release causes portability issues (#210)
- Support applying plans by column? (Or is it really 300x slower??) (#216)
- `fft(x,dim)` fails on Julia-1.7.0-rc1 (#220)
- First call to plan_rfft trashes the input (#226)

**Merged pull requests:**
- allow MKL 2022 (#228) (@KristofferC)
- Improve inferrability of dims_howmany (#231) (@timholy)

[Diff since v1.4.4](v1.4.4...v1.4.5)

**Merged pull requests:**
- remove asserts from precompile (#214) (@KristofferC)

[Diff since v1.4.3](v1.4.3...v1.4.4)

**Merged pull requests:**
- make FFTW relocatable, take 2 (#212) (@KristofferC)
- bump version (#213) (@KristofferC)

[Diff since v1.4.2](v1.4.2...v1.4.3)

**Merged pull requests:**
- Make FFTW relocatable for PackageCompiler (#207) (@staticfloat)

[Diff since v1.4.1](v1.4.1...v1.4.2)

**Closed issues:**
- Deadlock bug in FFTW 1.2.4 (#163)
- Omit the alignment check when using MKL's fftw3 wrapper? (#202)

**Merged pull requests:**
- Add a safepoint in the maybe_destroy_plan spin lock (#205) (@Octogonapus)