linuxPackages.sysdig: 0.20.0 -> 0.21.0

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/sysdig/versions.

These checks were done:

- built on NixOS
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/sysdig -h` got 0 exit code
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/sysdig --help` got 0 exit code
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/sysdig help` got 0 exit code
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/sysdig --version` and found version 0.21.0
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/sysdig -h` and found version 0.21.0
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/sysdig --help` and found version 0.21.0
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/csysdig -h` got 0 exit code
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/csysdig --help` got 0 exit code
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/csysdig help` got 0 exit code
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/csysdig -V` and found version 0.21.0
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/csysdig -v` and found version 0.21.0
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/csysdig --version` and found version 0.21.0
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/csysdig -h` and found version 0.21.0
- ran `/nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0/bin/csysdig --help` and found version 0.21.0
- found 0.21.0 with grep in /nix/store/q46s7qx6pq8wlwqgi6dcdjcb41qc0zn9-sysdig-0.21.0
- directory tree listing: https://gist.github.com/90f767f238a59aa31ac34058784510d7