upgrade pip

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

temporary remove delete from nightly

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

update to pypirc

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

fix Z3Prover#2309

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

new tag

Z3 version 4.8.3

Merge pull request Z3Prover#1881 from Z3Prover/revert-1880-c++17

Revert "Made Z3 compile for C++17 with MSVC"

bumping version number by 1 for release tagging

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

Official release Z3 4.6.0

Official release Z3 4.5.0