Add a security policy #119

Job	Run time
package-sdist	6s
lint	36s
package-wheel (manylinux, ubuntu-latest)	20m 46s
test (ubuntu-latest, 3.7)	3m 33s
package-wheel (macos, macos-latest)	5m 49s
test (ubuntu-latest, 3.8)	3m 4s
package-wheel (win, windows-latest)	4m 18s
test (ubuntu-latest, 3.9)	3m 33s
test (ubuntu-latest, 3.10)	2m 15s
test (ubuntu-latest, 3.11)	4m 9s
test (ubuntu-latest, 3.12)	3m 47s
test (macos-latest, 3.7)	15m 11s
test (macos-latest, 3.8)	8m 33s
test (macos-latest, 3.9)	9m 21s
test (macos-latest, 3.10)	10m 43s
test (macos-latest, 3.11)	7m 11s
test (macos-latest, 3.12)	7m 48s
test (windows-latest, 3.7)	11m 42s
test (windows-latest, 3.8)	10m 18s
test (windows-latest, 3.9)	9m 40s
test (windows-latest, 3.10)	11m 8s
test (windows-latest, 3.11)	10m 42s
test (windows-latest, 3.12)	11m 18s
publish	0s
	2h 55m 31s

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