bump to 0.3.1 #145

Job	Run time
lint	2m 1s
test 3.9 pandas 2.1.*	1m 19s
build on linux (x86_64 - auto)	2m 51s
test 3.9 pandas 2.2.*	1m 10s
build on linux (aarch64 - auto)	3m 9s
test 3.10 pandas 2.1.*	1m 30s
build on macos (x86_64 - auto)	1m 52s
test 3.10 pandas 2.2.*	1m 24s
build on macos (aarch64 - auto)	1m 53s
test 3.11 pandas 2.1.*	1m 32s
build on windows (x86_64 - auto)	5m 15s
test 3.11 pandas 2.2.*	1m 20s
build on windows (i686 - auto)	4m 51s
test 3.12 pandas 2.1.*	1m 22s
build on windows (aarch64 - auto)	5m 11s
test 3.12 pandas 2.2.*	1m 34s
build on linux (i686 - auto)	3m 55s
test 3.8 pandas none	1m 1s
build on linux (armv7 - auto)	2m 37s
test pypy3.8 pandas none	53s
build on linux (x86_64 - musllinux_1_1)	2m 29s
test pypy3.9 pandas none	58s
test pypy3.10 pandas none	59s
test 3.13 pandas 2.2.*	49s
build on linux (aarch64 - musllinux_1_1)	2m 23s
build on linux (ppc64le - auto)	2m 32s
build on linux (s390x - auto)	2m 26s
check	4s
release	3m 44s
	1h 3m 4s

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