Update PDF Convertors

[dleffler]

All of the optional PDF packages have newer versions and should be updated

• MPDF - v8.1.1 (v8.0.8 in Exp resources)
• DOMPDF - v2.0.0 (v0.86 in Exp resources)
• HTML2PDF - v5.2.4 (v5.2.2 in Exp resources)

And helper libraries

• TCPDF - v6.4.4 (v6.3.5 in Exp resources)
• FPDI - v2.3.6 (v2.3.5 in Exp resources)
• Random - v2.0.20 (v2.0.19 in Exp resources)
• Log - v1.1.4 (v1.1.3 in Exp resources)

[dleffler]

We updated these in the v2.7.0 release