pjsip: 2.7.1 -> 2.7.2

Semi-automatic update. These checks were performed:

- built on NixOS
- ran `/nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2/bin/pjsua -h` got 0 exit code
- ran `/nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2/bin/pjsua --help` got 0 exit code
- ran `/nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2/bin/pjsua help` got 0 exit code
- ran `/nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2/bin/pjsua -V` and found version 2.7.2
- ran `/nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2/bin/pjsua -v` and found version 2.7.2
- ran `/nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2/bin/pjsua --version` and found version 2.7.2
- ran `/nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2/bin/pjsua version` and found version 2.7.2
- ran `/nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2/bin/pjsua -h` and found version 2.7.2
- ran `/nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2/bin/pjsua --help` and found version 2.7.2
- ran `/nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2/bin/pjsua help` and found version 2.7.2
- found 2.7.2 with grep in /nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2
- found 2.7.2 in filename of file in /nix/store/3wqj8kyahgi1r25wp8vfhhsg0m1mzpkx-pjsip-2.7.2

cc "@viric @olynch"