Update fipp version due to errors with clojure 1.12.0-alpha7

[mikeananev]

Please, update fipp version up to 0.6.26 to avoid compile error.

fipp, a dependency of hashp, used to use a hack to access a private var in clojure.instant. That var has been removed, so library is broken.

How to reproduce bug:

mike@mbp03  clj -Sdeps '{:deps {org.clojure/clojure {:mvn/version "1.12.0-alpha7"} hashp/hashp {:mvn/version "0.2.2"}}}'
Clojure 1.12.0-alpha7
user=> (require '[hashp.core])
Syntax error compiling var at (fipp/ednize/instant.clj:11:13).
Unable to resolve var: clojure.instant/thread-local-utc-timestamp-format in this context