Add security override for sha1 #20

Job	Run time
cmake-offline-googletest-src	4m 18s
ubuntu-latest [CC gcc; botan; shared libs on; GnuPG stable]	4m 7s
cmake-offline-googletest	4m 25s
ubuntu-latest [CC clang; botan; shared libs on; GnuPG stable]	4m 15s
ubuntu-latest [CC gcc; openssl; shared libs on; GnuPG stable]	4m 0s
ubuntu-latest [CC clang; openssl; shared libs on; GnuPG stable]	4m 10s
system-sexpp, sexpp shared libs on, rnp shared libs on	2m 47s
ubuntu-20.04 [CC gcc; openssl; shared libs on; GnuPG stable]	3m 45s
system-sexpp, sexpp shared libs on, rnp shared libs off	2m 54s
ubuntu-latest [CC gcc; botan; shared libs off; GnuPG stable]	4m 16s
system-sexpp, sexpp shared libs off, rnp shared libs on	3m 1s
system-sexpp, sexpp shared libs off, rnp shared libs off	2m 55s
package-source	29s
package	1m 15s
debian-tests	13s
	46m 50s

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