Fixed sprint tests, Introducing golangci-lint

[ebinf]

Description of the PR

Fixed sprint tests, they should run fine now. Replaced staticcheck by golangci-lint as suggested by @gh0st42. Also fixing the errors already present.

Review checklist

(based on the work of Karl E. Wiegers)

Structure

• [x] Does the code completely and correctly implement the design?
• [x] Is the code well-structured, consistent in style, and consistently formatted?
• [x] Are there any uncalled or unneeded procedures or any unreachable code?
• [x] Are there any leftover stubs or test routines in the code?
• [x] Can any code be replaced by calls to external reusable components or library functions?
• [x] Are there any blocks of repeated code that could be condensed into a single procedure?
• [x] Are symbolics used rather than “magic number” constants or string constants?
• [x] Are any modules excessively complex and should be restructured or split into multiple routines?

Documentation

• [x] Is the code clearly and adequately documented with an easy-to-maintain commenting style?
• [x] Are all comments consistent with the code?

Variables

• [x] Are all variables properly defined with meaningful, consistent, and clear names?
• [x] Are there any redundant or unused variables?

Arithmetic Operations

• [x] Does the code avoid comparing floating-point numbers for equality?
• [x] Are divisors tested for zero or noise?

Loops and Branches

• [x] Are all loops, branches, and logic constructs complete and correct?
• [x] Are all loops, branches, and logic constructs properly nested and avoid unnecessary nesting?
• [x] Can any statements that are enclosed within loops be placed outside the loops?

Defensive Programming

• [x] Are imported data and input arguments tested for validity and completeness?
• [x] Are files checked for existence before attempting to access them?