Add cast for size_t while logging

[pvyawaha]

Issue #, if available: #199

Description of changes:
This change adds a cast when logging size_t type .

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[ser90368141]

Hi pvyawaha!
Please add casting in these two places.

ota-for-aws-iot-embedded-sdk/source/ota.c

Lines 1627 to 1630 in 5d7c7f6

	LogError( ( "Insufficient user memory: "
	"[key: valueLength]=[%s: %lu]",
	pKey,
	valueLength ) );

ota-for-aws-iot-embedded-sdk/source/ota.c

Lines 2003 to 2004 in 5d7c7f6

	LogDebug( ( "Failed to parse custom job document: OtaJobParseErr_t=%s, jobIdLength=%lu",
	OTA_JobParse_strerror( jobDoc.parseErr ), jobDoc.jobIdLength ) );

I added these changes and the library built successfully.
Thank!

[gkwicker]

See comments.