fix(ci): fix docs being deployed in an unintended subdirectory #68

Job	Run time
docs	2m 15s
lint	35s
test (libcoap-sys, openssl, msrv)	2m 3s
test (libcoap-sys, openssl, stable)	1m 58s
test (libcoap-sys, openssl, nightly)	2m 12s
test (libcoap-sys, gnutls, msrv)	59s
test (libcoap-sys, gnutls, stable)	57s
test (libcoap-sys, gnutls, nightly)	55s
test (libcoap-sys, tinydtls, msrv)	1m 1s
test (libcoap-sys, tinydtls, stable)	1m 5s
test (libcoap-sys, tinydtls, nightly)	57s
test (libcoap-sys, mbedtls, msrv)	1m 0s
test (libcoap-sys, mbedtls, stable)	52s
test (libcoap-sys, mbedtls, nightly)	1m 2s
test (libcoap-rs, openssl, msrv)	2m 6s
test (libcoap-rs, openssl, stable)	2m 11s
test (libcoap-rs, openssl, nightly)	2m 21s
test (libcoap-rs, gnutls, msrv)	1m 8s
test (libcoap-rs, gnutls, stable)	1m 13s
test (libcoap-rs, gnutls, nightly)	1m 7s
test (libcoap-rs, tinydtls, msrv)	1m 2s
test (libcoap-rs, tinydtls, stable)	1m 7s
test (libcoap-rs, tinydtls, nightly)	1m 5s
test (libcoap-rs, mbedtls, msrv)	1m 7s
test (libcoap-rs, mbedtls, stable)	59s
test (libcoap-rs, mbedtls, nightly)	1m 6s
	34m 23s

Provide feedback